linux/net/core/dst.c

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/*
* net/core/dst.c Protocol independent destination cache.
*
* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
*
*/
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
#include <linux/workqueue.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/string.h>
#include <linux/types.h>
#include <net/net_namespace.h>
#include <net/dst.h>
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
/*
* Theory of operations:
* 1) We use a list, protected by a spinlock, to add
* new entries from both BH and non-BH context.
* 2) In order to keep spinlock held for a small delay,
* we use a second list where are stored long lived
* entries, that are handled by the garbage collect thread
* fired by a workqueue.
* 3) This list is guarded by a mutex,
* so that the gc_task and dst_dev_event() can be synchronized.
*/
#if RT_CACHE_DEBUG >= 2
static atomic_t dst_total = ATOMIC_INIT(0);
#endif
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
/*
* We want to keep lock & list close together
* to dirty as few cache lines as possible in __dst_free().
* As this is not a very strong hint, we dont force an alignment on SMP.
*/
static struct {
spinlock_t lock;
struct dst_entry *list;
unsigned long timer_inc;
unsigned long timer_expires;
} dst_garbage = {
.lock = __SPIN_LOCK_UNLOCKED(dst_garbage.lock),
.timer_inc = DST_GC_MAX,
};
static void dst_gc_task(struct work_struct *work);
static void ___dst_free(struct dst_entry * dst);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
static DECLARE_DELAYED_WORK(dst_gc_work, dst_gc_task);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
static DEFINE_MUTEX(dst_gc_mutex);
/*
* long lived entries are maintained in this list, guarded by dst_gc_mutex
*/
static struct dst_entry *dst_busy_list;
static void dst_gc_task(struct work_struct *work)
{
int delayed = 0;
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
int work_performed = 0;
unsigned long expires = ~0L;
struct dst_entry *dst, *next, head;
struct dst_entry *last = &head;
#if RT_CACHE_DEBUG >= 2
ktime_t time_start = ktime_get();
struct timespec elapsed;
#endif
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
mutex_lock(&dst_gc_mutex);
next = dst_busy_list;
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
loop:
while ((dst = next) != NULL) {
next = dst->next;
prefetch(&next->next);
if (likely(atomic_read(&dst->__refcnt))) {
last->next = dst;
last = dst;
delayed++;
continue;
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
work_performed++;
dst = dst_destroy(dst);
if (dst) {
/* NOHASH and still referenced. Unless it is already
* on gc list, invalidate it and add to gc list.
*
* Note: this is temporary. Actually, NOHASH dst's
* must be obsoleted when parent is obsoleted.
* But we do not have state "obsoleted, but
* referenced by parent", so it is right.
*/
if (dst->obsolete > 1)
continue;
___dst_free(dst);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
dst->next = next;
next = dst;
}
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
spin_lock_bh(&dst_garbage.lock);
next = dst_garbage.list;
if (next) {
dst_garbage.list = NULL;
spin_unlock_bh(&dst_garbage.lock);
goto loop;
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
last->next = NULL;
dst_busy_list = head.next;
if (!dst_busy_list)
dst_garbage.timer_inc = DST_GC_MAX;
else {
/*
* if we freed less than 1/10 of delayed entries,
* we can sleep longer.
*/
if (work_performed <= delayed/10) {
dst_garbage.timer_expires += dst_garbage.timer_inc;
if (dst_garbage.timer_expires > DST_GC_MAX)
dst_garbage.timer_expires = DST_GC_MAX;
dst_garbage.timer_inc += DST_GC_INC;
} else {
dst_garbage.timer_inc = DST_GC_INC;
dst_garbage.timer_expires = DST_GC_MIN;
}
expires = dst_garbage.timer_expires;
/*
* if the next desired timer is more than 4 seconds in the future
* then round the timer to whole seconds
*/
if (expires > 4*HZ)
expires = round_jiffies_relative(expires);
schedule_delayed_work(&dst_gc_work, expires);
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
spin_unlock_bh(&dst_garbage.lock);
mutex_unlock(&dst_gc_mutex);
#if RT_CACHE_DEBUG >= 2
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
elapsed = ktime_to_timespec(ktime_sub(ktime_get(), time_start));
printk(KERN_DEBUG "dst_total: %d delayed: %d work_perf: %d"
" expires: %lu elapsed: %lu us\n",
atomic_read(&dst_total), delayed, work_performed,
expires,
elapsed.tv_sec * USEC_PER_SEC + elapsed.tv_nsec / NSEC_PER_USEC);
#endif
}
int dst_discard(struct sk_buff *skb)
{
kfree_skb(skb);
return 0;
}
EXPORT_SYMBOL(dst_discard);
void * dst_alloc(struct dst_ops * ops)
{
struct dst_entry * dst;
if (ops->gc && atomic_read(&ops->entries) > ops->gc_thresh) {
if (ops->gc(ops))
return NULL;
}
dst = kmem_cache_zalloc(ops->kmem_cachep, GFP_ATOMIC);
if (!dst)
return NULL;
atomic_set(&dst->__refcnt, 0);
dst->ops = ops;
dst->lastuse = jiffies;
dst->path = dst;
dst->input = dst->output = dst_discard;
#if RT_CACHE_DEBUG >= 2
atomic_inc(&dst_total);
#endif
atomic_inc(&ops->entries);
return dst;
}
static void ___dst_free(struct dst_entry * dst)
{
/* The first case (dev==NULL) is required, when
protocol module is unloaded.
*/
if (dst->dev == NULL || !(dst->dev->flags&IFF_UP)) {
dst->input = dst->output = dst_discard;
}
dst->obsolete = 2;
}
void __dst_free(struct dst_entry * dst)
{
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
spin_lock_bh(&dst_garbage.lock);
___dst_free(dst);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
dst->next = dst_garbage.list;
dst_garbage.list = dst;
if (dst_garbage.timer_inc > DST_GC_INC) {
dst_garbage.timer_inc = DST_GC_INC;
dst_garbage.timer_expires = DST_GC_MIN;
net: fix scheduling of dst_gc_task by __dst_free The dst garbage collector dst_gc_task() may not be scheduled as we expect it to be in __dst_free(). Indeed, when the dst_gc_timer was replaced by the delayed_work dst_gc_work, the mod_timer() call used to schedule the garbage collector at an earlier date was replaced by a schedule_delayed_work() (see commit 86bba269d08f0c545ae76c90b56727f65d62d57f). But, the behaviour of mod_timer() and schedule_delayed_work() is different in the way they handle the delay. mod_timer() stops the timer and re-arm it with the new given delay, whereas schedule_delayed_work() only check if the work is already queued in the workqueue (and queue it (with delay) if it is not) BUT it does NOT take into account the new delay (even if the new delay is earlier in time). schedule_delayed_work() returns 0 if it didn't queue the work, but we don't check the return code in __dst_free(). If I understand the code in __dst_free() correctly, we want dst_gc_task to be queued after DST_GC_INC jiffies if we pass the test (and not in some undetermined time in the future), so I think we should add a call to cancel_delayed_work() before schedule_delayed_work(). Patch below. Or we should at least test the return code of schedule_delayed_work(), and reset the values of dst_garbage.timer_inc and dst_garbage.timer_expires back to their former values if schedule_delayed_work() failed. Otherwise the subsequent calls to __dst_free will test the wrong values and assume wrong thing about when the garbage collector is supposed to be scheduled. dst_gc_task() also calls schedule_delayed_work() without checking its return code (or calling cancel_scheduled_work() first), but it should fine there: dst_gc_task is the routine of the delayed_work, so no dst_gc_work should be pending in the queue when it's running. Signed-off-by: Benjamin Thery <benjamin.thery@bull.net> Acked-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-12 23:16:37 +00:00
cancel_delayed_work(&dst_gc_work);
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
schedule_delayed_work(&dst_gc_work, dst_garbage.timer_expires);
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
spin_unlock_bh(&dst_garbage.lock);
}
struct dst_entry *dst_destroy(struct dst_entry * dst)
{
struct dst_entry *child;
struct neighbour *neigh;
struct hh_cache *hh;
smp_rmb();
again:
neigh = dst->neighbour;
hh = dst->hh;
child = dst->child;
dst->hh = NULL;
if (hh && atomic_dec_and_test(&hh->hh_refcnt))
kfree(hh);
if (neigh) {
dst->neighbour = NULL;
neigh_release(neigh);
}
atomic_dec(&dst->ops->entries);
if (dst->ops->destroy)
dst->ops->destroy(dst);
if (dst->dev)
dev_put(dst->dev);
#if RT_CACHE_DEBUG >= 2
atomic_dec(&dst_total);
#endif
kmem_cache_free(dst->ops->kmem_cachep, dst);
dst = child;
if (dst) {
int nohash = dst->flags & DST_NOHASH;
if (atomic_dec_and_test(&dst->__refcnt)) {
/* We were real parent of this dst, so kill child. */
if (nohash)
goto again;
} else {
/* Child is still referenced, return it for freeing. */
if (nohash)
return dst;
/* Child is still in his hash table */
}
}
return NULL;
}
void dst_release(struct dst_entry *dst)
{
if (dst) {
net: speedup dst_release() During tbench/oprofile sessions, I found that dst_release() was in third position. CPU: Core 2, speed 2999.68 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 483726 9.0185 __copy_user_zeroing_intel 191466 3.5697 __copy_user_intel 185475 3.4580 dst_release 175114 3.2648 ip_queue_xmit 153447 2.8608 tcp_sendmsg 108775 2.0280 tcp_recvmsg 102659 1.9140 sysenter_past_esp 101450 1.8914 tcp_current_mss 95067 1.7724 __copy_from_user_ll 86531 1.6133 tcp_transmit_skb Of course, all CPUS fight on the dst_entry associated with 127.0.0.1 Instead of first checking the refcount value, then decrement it, we use atomic_dec_return() to help CPU to make the right memory transaction (ie getting the cache line in exclusive mode) dst_release() is now at the fifth position, and tbench a litle bit faster ;) CPU: Core 2, speed 3000.1 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 647107 8.8072 __copy_user_zeroing_intel 258840 3.5229 ip_queue_xmit 258302 3.5155 __copy_user_intel 209629 2.8531 tcp_sendmsg 165632 2.2543 dst_release 149232 2.0311 tcp_current_mss 147821 2.0119 tcp_recvmsg 137893 1.8767 sysenter_past_esp 127473 1.7349 __copy_from_user_ll 121308 1.6510 ip_finish_output 118510 1.6129 tcp_transmit_skb 109295 1.4875 tcp_v4_rcv Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-14 08:53:54 +00:00
int newrefcnt;
smp_mb__before_atomic_dec();
net: speedup dst_release() During tbench/oprofile sessions, I found that dst_release() was in third position. CPU: Core 2, speed 2999.68 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 483726 9.0185 __copy_user_zeroing_intel 191466 3.5697 __copy_user_intel 185475 3.4580 dst_release 175114 3.2648 ip_queue_xmit 153447 2.8608 tcp_sendmsg 108775 2.0280 tcp_recvmsg 102659 1.9140 sysenter_past_esp 101450 1.8914 tcp_current_mss 95067 1.7724 __copy_from_user_ll 86531 1.6133 tcp_transmit_skb Of course, all CPUS fight on the dst_entry associated with 127.0.0.1 Instead of first checking the refcount value, then decrement it, we use atomic_dec_return() to help CPU to make the right memory transaction (ie getting the cache line in exclusive mode) dst_release() is now at the fifth position, and tbench a litle bit faster ;) CPU: Core 2, speed 3000.1 MHz (estimated) Counted CPU_CLK_UNHALTED events (Clock cycles when not halted) with a unit mask of 0x00 (Unhalted core cycles) count 100000 samples % symbol name 647107 8.8072 __copy_user_zeroing_intel 258840 3.5229 ip_queue_xmit 258302 3.5155 __copy_user_intel 209629 2.8531 tcp_sendmsg 165632 2.2543 dst_release 149232 2.0311 tcp_current_mss 147821 2.0119 tcp_recvmsg 137893 1.8767 sysenter_past_esp 127473 1.7349 __copy_from_user_ll 121308 1.6510 ip_finish_output 118510 1.6129 tcp_transmit_skb 109295 1.4875 tcp_v4_rcv Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-14 08:53:54 +00:00
newrefcnt = atomic_dec_return(&dst->__refcnt);
WARN_ON(newrefcnt < 0);
}
}
EXPORT_SYMBOL(dst_release);
/* Dirty hack. We did it in 2.2 (in __dst_free),
* we have _very_ good reasons not to repeat
* this mistake in 2.3, but we have no choice
* now. _It_ _is_ _explicit_ _deliberate_
* _race_ _condition_.
*
* Commented and originally written by Alexey.
*/
static inline void dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int unregister)
{
if (dst->ops->ifdown)
dst->ops->ifdown(dst, dev, unregister);
if (dev != dst->dev)
return;
if (!unregister) {
dst->input = dst->output = dst_discard;
} else {
dst->dev = dev_net(dst->dev)->loopback_dev;
dev_hold(dst->dev);
dev_put(dev);
if (dst->neighbour && dst->neighbour->dev == dev) {
dst->neighbour->dev = dst->dev;
dev_hold(dst->dev);
dev_put(dev);
}
}
}
static int dst_dev_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = ptr;
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
struct dst_entry *dst, *last = NULL;
switch (event) {
case NETDEV_UNREGISTER:
case NETDEV_DOWN:
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
mutex_lock(&dst_gc_mutex);
for (dst = dst_busy_list; dst; dst = dst->next) {
last = dst;
dst_ifdown(dst, dev, event != NETDEV_DOWN);
}
spin_lock_bh(&dst_garbage.lock);
dst = dst_garbage.list;
dst_garbage.list = NULL;
spin_unlock_bh(&dst_garbage.lock);
if (last)
last->next = dst;
else
dst_busy_list = dst;
for (; dst; dst = dst->next) {
dst_ifdown(dst, dev, event != NETDEV_DOWN);
}
[PATCH] NET : convert IP route cache garbage collection from softirq processing to a workqueue When the periodic IP route cache flush is done (every 600 seconds on default configuration), some hosts suffer a lot and eventually trigger the "soft lockup" message. dst_run_gc() is doing a scan of a possibly huge list of dst_entries, eventually freeing some (less than 1%) of them, while holding the dst_lock spinlock for the whole scan. Then it rearms a timer to redo the full thing 1/10 s later... The slowdown can last one minute or so, depending on how active are the tcp sessions. This second version of the patch converts the processing from a softirq based one to a workqueue. Even if the list of entries in garbage_list is huge, host is still responsive to softirqs and can make progress. Instead of resetting gc timer to 0.1 second if one entry was freed in a gc run, we do this if more than 10% of entries were freed. Before patch : Aug 16 06:21:37 SRV1 kernel: BUG: soft lockup detected on CPU#0! Aug 16 06:21:37 SRV1 kernel: Aug 16 06:21:37 SRV1 kernel: Call Trace: Aug 16 06:21:37 SRV1 kernel: <IRQ> [<ffffffff802286f0>] wake_up_process+0x10/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80251e09>] softlockup_tick+0xe9/0x110 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd380>] dst_run_gc+0x0/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802376f3>] run_local_timers+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802379c7>] update_process_times+0x57/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80216034>] smp_local_timer_interrupt+0x34/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802165cc>] smp_apic_timer_interrupt+0x5c/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020a816>] apic_timer_interrupt+0x66/0x70 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3d3>] dst_run_gc+0x53/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd3c6>] dst_run_gc+0x46/0x140 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80237148>] run_timer_softirq+0x148/0x1c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8023340c>] __do_softirq+0x6c/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8020ad6c>] call_softirq+0x1c/0x30 Aug 16 06:21:37 SRV1 kernel: <EOI> [<ffffffff8020cb34>] do_softirq+0x34/0x90 Aug 16 06:21:37 SRV1 kernel: [<ffffffff802331cf>] local_bh_enable_ip+0x3f/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422913>] _spin_unlock_bh+0x13/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803dfde8>] rt_garbage_collect+0x1d8/0x320 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803cd4dd>] dst_alloc+0x1d/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e1433>] __ip_route_output_key+0x573/0x800 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c02e2>] sock_common_recvmsg+0x32/0x50 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803e16dc>] ip_route_output_flow+0x1c/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80400160>] tcp_v4_connect+0x150/0x610 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803ebf07>] inet_bind_bucket_create+0x17/0x60 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8040cd16>] inet_stream_connect+0xa6/0x2c0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c0bdf>] lock_sock_nested+0xcf/0xe0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80422981>] _spin_lock_bh+0x11/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be551>] sys_connect+0x71/0xa0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803eee3f>] tcp_setsockopt+0x1f/0x30 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803c030f>] sock_common_setsockopt+0xf/0x20 Aug 16 06:21:37 SRV1 kernel: [<ffffffff803be4bd>] sys_setsockopt+0x9d/0xc0 Aug 16 06:21:37 SRV1 kernel: [<ffffffff8028881e>] sys_ioctl+0x5e/0x80 Aug 16 06:21:37 SRV1 kernel: [<ffffffff80209c4e>] system_call+0x7e/0x83 After patch : (RT_CACHE_DEBUG set to 2 to get following traces) dst_total: 75469 delayed: 74109 work_perf: 141 expires: 150 elapsed: 8092 us dst_total: 78725 delayed: 73366 work_perf: 743 expires: 400 elapsed: 8542 us dst_total: 86126 delayed: 71844 work_perf: 1522 expires: 775 elapsed: 8849 us dst_total: 100173 delayed: 68791 work_perf: 3053 expires: 1256 elapsed: 9748 us dst_total: 121798 delayed: 64711 work_perf: 4080 expires: 1997 elapsed: 10146 us dst_total: 154522 delayed: 58316 work_perf: 6395 expires: 25 elapsed: 11402 us dst_total: 154957 delayed: 58252 work_perf: 64 expires: 150 elapsed: 6148 us dst_total: 157377 delayed: 57843 work_perf: 409 expires: 400 elapsed: 6350 us dst_total: 163745 delayed: 56679 work_perf: 1164 expires: 775 elapsed: 7051 us dst_total: 176577 delayed: 53965 work_perf: 2714 expires: 1389 elapsed: 8120 us dst_total: 198993 delayed: 49627 work_perf: 4338 expires: 1997 elapsed: 8909 us dst_total: 226638 delayed: 46865 work_perf: 2762 expires: 2748 elapsed: 7351 us I successfully reduced the IP route cache of many hosts by a four factor thanks to this patch. Previously, I had to disable "ip route flush cache" to avoid crashes. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-09-12 12:29:01 +00:00
mutex_unlock(&dst_gc_mutex);
break;
}
return NOTIFY_DONE;
}
static struct notifier_block dst_dev_notifier = {
.notifier_call = dst_dev_event,
};
void __init dst_init(void)
{
register_netdevice_notifier(&dst_dev_notifier);
}
EXPORT_SYMBOL(__dst_free);
EXPORT_SYMBOL(dst_alloc);
EXPORT_SYMBOL(dst_destroy);