memblock_set_node() operates in three steps - break regions crossing
boundaries, set nid and merge back regions. This patch separates the
first part into a separate function - memblock_isolate_range(), which
breaks regions crossing range boundaries and returns range index range
for regions properly contained in the specified memory range.
This doesn't introduce any behavior change and will be used to further
unify region handling.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
memblock_init() initializes arrays for regions and memblock itself;
however, all these can be done with struct initializers and
memblock_init() can be removed. This patch kills memblock_init() and
initializes memblock with struct initializer.
The only difference is that the first dummy entries don't have .nid
set to MAX_NUMNODES initially. This doesn't cause any behavior
difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: "H. Peter Anvin" <hpa@zytor.com>
memblock no longer depends on having one more entry at the end during
addition making the sentinel entries at the end of region arrays not
too useful. Remove the sentinels. This eases further updates.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Add __memblock_dump_all() which dumps memblock configuration whether
memblock_debug is enabled or not.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Make memblock_double_array(), __memblock_alloc_base() and
memblock_alloc_nid() use memblock_reserve() instead of calling
memblock_add_region() with reserved array directly. This eases
debugging and updates to memblock_add_region().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
memblock_{add|remove|free|reserve}() return either 0 or -errno but had
long as return type. Chage it to int. Also, drop 'extern' from all
prototypes in memblock.h - they are unnecessary and used
inconsistently (especially if mm.h is included in the picture).
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Some trace shows lots of bdi_dirty=0 lines where it's actually some
small value if w/o the accounting errors in the per-cpu bdi stats.
In this case the max pause time should really be set to the smallest
(non-zero) value to avoid IO queue underrun and improve throughput.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
On a system with 1 local mount and 1 NFS mount, if the NFS server
becomes not responding when dd to the NFS mount, the NFS dirty pages may
exceed the global dirty limit and _every_ task involving writing will be
blocked. The whole system appears unresponsive.
The workaround is to permit through the bdi's that only has a small
number of dirty pages. The number chosen (bdi_stat_error pages) is not
enough to enable the local disk to run in optimal throughput, however is
enough to make the system responsive on a broken NFS mount. The user can
then kill the dirtiers on the NFS mount and increase the global dirty
limit to bring up the local disk's throughput.
It risks allowing dirty pages to grow much larger than the global dirty
limit when there are 1000+ mounts, however that's very unlikely to happen,
especially in low memory profiles.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
We do "floating proportions" to let active devices to grow its target
share of dirty pages and stalled/inactive devices to decrease its target
share over time.
It works well except in the case of "an inactive disk suddenly goes
busy", where the initial target share may be too small. To mitigate
this, bdi_position_ratio() has the below line to raise a small
bdi_thresh when it's safe to do so, so that the disk be feed with enough
dirty pages for efficient IO and in turn fast rampup of bdi_thresh:
bdi_thresh = max(bdi_thresh, (limit - dirty) / 8);
balance_dirty_pages() normally does negative feedback control which
adjusts ratelimit to balance the bdi dirty pages around the target.
In some extreme cases when that is not enough, it will have to block
the tasks completely until the bdi dirty pages drop below bdi_thresh.
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Commit 30765b92 ("slab, lockdep: Annotate the locks before using
them") moves the init_lock_keys() call from after g_cpucache_up =
FULL, to before it. And overlooks the fact that init_node_lock_keys()
tests for it and ignores everything !FULL.
Introduce a LATE stage and change the lockdep test to be <LATE.
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently write(2) to a file is not interruptible by any signal.
Sometimes this is desirable, e.g. when you want to quickly kill a
process hogging your disk. Also, with commit 499d05ecf9 ("mm: Make
task in balance_dirty_pages() killable"), it's necessary to abort the
current write accordingly to avoid it quickly dirtying lots more pages
at unthrottled rate.
This patch makes write interruptible by SIGKILL. We do not allow write
to be interruptible by any other signal because that has larger
potential of screwing some badly written applications.
Reported-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Tested-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Acked-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
slub: avoid potential NULL dereference or corruption
slub: use irqsafe_cpu_cmpxchg for put_cpu_partial
slub: move discard_slab out of node lock
slub: use correct parameter to add a page to partial list tail
* 'for-3.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: explain why per_cpu_ptr_to_phys() is more complicated than necessary
percpu: fix chunk range calculation
percpu: rename pcpu_mem_alloc to pcpu_mem_zalloc
Conflicts & resolutions:
* arch/x86/xen/setup.c
dc91c728fd "xen: allow extra memory to be in multiple regions"
24aa07882b "memblock, x86: Replace memblock_x86_reserve/free..."
conflicted on xen_add_extra_mem() updates. The resolution is
trivial as the latter just want to replace
memblock_x86_reserve_range() with memblock_reserve().
* drivers/pci/intel-iommu.c
166e9278a3 "x86/ia64: intel-iommu: move to drivers/iommu/"
5dfe8660a3 "bootmem: Replace work_with_active_regions() with..."
conflicted as the former moved the file under drivers/iommu/.
Resolved by applying the chnages from the latter on the moved
file.
* mm/Kconfig
6661672053 "memblock: add NO_BOOTMEM config symbol"
c378ddd53f "memblock, x86: Make ARCH_DISCARD_MEMBLOCK a config option"
conflicted trivially. Both added config options. Just
letting both add their own options resolves the conflict.
* mm/memblock.c
d1f0ece6cd "mm/memblock.c: small function definition fixes"
ed7b56a799 "memblock: Remove memblock_memory_can_coalesce()"
confliected. The former updates function removed by the
latter. Resolution is trivial.
Signed-off-by: Tejun Heo <tj@kernel.org>
show_slab_objects() can trigger NULL dereferences or memory corruption.
Another cpu can change its c->page to NULL or c->node to NUMA_NO_NODE
while we use them.
Use ACCESS_ONCE(c->page) and ACCESS_ONCE(c->node) to make sure this
cannot happen.
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The cmpxchg must be irq safe. The fallback for this_cpu_cmpxchg only
disables preemption which results in per cpu partial page operation
potentially failing on non x86 platforms.
This patch fixes the following problem reported by Christian Kujau:
I seem to hit it with heavy disk & cpu IO is in progress on this
PowerBook
G4. Full dmesg & .config: http://nerdbynature.de/bits/3.2.0-rc1/oops/
I've enabled some debug options and now it really points to slub.c:2166
http://nerdbynature.de/bits/3.2.0-rc1/oops/oops4m.jpg
With debug options enabled I'm currently in the xmon debugger, not sure
what to make of it yet, I'll try to get something useful out of it :)
Reported-by: Christian Kujau <lists@nerdbynature.de>
Tested-by: Christian Kujau <lists@nerdbynature.de>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Add comments about current per_cpu_ptr_to_phys implementation to
explain why the logic is more complicated than necessary.
-tj: relocated comment into kerneldoc comment
Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
* 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: remove vm_dirties and task->dirties
writeback: hard throttle 1000+ dd on a slow USB stick
mm: Make task in balance_dirty_pages() killable
Percpu allocator recorded the cpus which map to the first and last
units in pcpu_first/last_unit_cpu respectively and used them to
determine the address range of a chunk - e.g. it assumed that the
first unit has the lowest address in a chunk while the last unit has
the highest address.
This simply isn't true. Groups in a chunk can have arbitrary positive
or negative offsets from the previous one and there is no guarantee
that the first unit occupies the lowest offset while the last one the
highest.
Fix it by actually comparing unit offsets to determine cpus occupying
the lowest and highest offsets. Also, rename pcu_first/last_unit_cpu
to pcpu_low/high_unit_cpu to avoid confusion.
The chunk address range is used to flush cache on vmalloc area
map/unmap and decide whether a given address is in the first chunk by
per_cpu_ptr_to_phys() and the bug was discovered by invalid
per_cpu_ptr_to_phys() translation for crash_note.
Kudos to Dave Young for tracking down the problem.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: WANG Cong <xiyou.wangcong@gmail.com>
Reported-by: Dave Young <dyoung@redhat.com>
Tested-by: Dave Young <dyoung@redhat.com>
LKML-Reference: <4EC21F67.10905@redhat.com>
Cc: stable @kernel.org
Currently pcpu_mem_alloc() is implemented always return zeroed memory.
So rename it to make user like pcpu_get_pages_and_bitmap() know don't
reinit it.
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
The existing vm_area_register_early() allows for early vmalloc space
allocation. However upcoming cleanups in the ARM architecture require
that some fixed locations in the vmalloc area be reserved also very early.
The name "vm_area_register_early" would have been a good name for the
reservation part without the allocation. Since it is already in use with
different semantics, let's create vm_area_add_early() instead.
Both vm_area_register_early() and vm_area_add_early() can be used together
meaning that the former is now implemented using the later where it is
ensured that no conflicting areas are added, but no attempt is made to
make the allocation scheme in vm_area_register_early() more sophisticated.
After all, you must know what you're doing when using those functions.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
* 'stable/for-linus-fixes-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen-gntalloc: signedness bug in add_grefs()
xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()
xen-gntdev: integer overflow in gntdev_alloc_map()
xen:pvhvm: enable PVHVM VCPU placement when using more than 32 CPUs.
xen/balloon: Avoid OOM when requesting highmem
xen: Remove hanging references to CONFIG_XEN_PLATFORM_PCI
xen: map foreign pages for shared rings by updating the PTEs directly
* 'for-linus' of git://git.kernel.dk/linux-block:
block: add missed trace_block_plug
paride: fix potential information leak in pg_read()
bio: change some signed vars to unsigned
block: avoid unnecessary plug list flush
cciss: auto engage SCSI mid layer at driver load time
loop: cleanup set_status interface
include/linux/bio.h: use a static inline function for bio_integrity_clone()
loop: prevent information leak after failed read
block: Always check length of all iov entries in blk_rq_map_user_iov()
The Windows driver .inf disables ASPM on all cciss devices. Do the same.
backing-dev: ensure wakeup_timer is deleted
block: Revert "[SCSI] genhd: add a new attribute "alias" in gendisk"
The sleep based balance_dirty_pages() can pause at most MAX_PAUSE=200ms
on every 1 4KB-page, which means it cannot throttle a task under
4KB/200ms=20KB/s. So when there are more than 512 dd writing to a
10MB/s USB stick, its bdi dirty pages could grow out of control.
Even if we can increase MAX_PAUSE, the minimal (task_ratelimit = 1)
means a limit of 4KB/s.
They can eventually be safeguarded by the global limit check
(nr_dirty < dirty_thresh). However if someone is also writing to an
HDD at the same time, it'll get poor HDD write performance.
We at least want to maintain good write performance for other devices
when one device is attacked by some "massive parallel" workload, or
suffers from slow write bandwidth, or somehow get stalled due to some
error condition (eg. NFS server not responding).
For a stalled device, we need to completely block its dirtiers, too,
before its bdi dirty pages grow all the way up to the global limit and
leave no space for the other functional devices.
So change the loop exit condition to
/*
* Always enforce global dirty limit; also enforce bdi dirty limit
* if the normal max_pause sleeps cannot keep things under control.
*/
if (nr_dirty < dirty_thresh &&
(bdi_dirty < bdi_thresh || bdi->dirty_ratelimit > 1))
break;
which can be further simplified to
if (task_ratelimit)
break;
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
When mapping a foreign page with xenbus_map_ring_valloc() with the
GNTTABOP_map_grant_ref hypercall, set the GNTMAP_contains_pte flag and
pass a pointer to the PTE (in init_mm).
After the page is mapped, the usual fault mechanism can be used to
update additional MMs. This allows the vmalloc_sync_all() to be
removed from alloc_vm_area().
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
[v1: Squashed fix by Michal for no-mmu case]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
There is no reason why task in balance_dirty_pages() shouldn't be killable
and it helps in recovering from some error conditions (like when filesystem
goes in error state and cannot accept writeback anymore but we still want to
kill processes using it to be able to unmount it).
There will be follow up patches to further abort the generic_perform_write()
and other filesystem write loops, to avoid large write + SIGKILL combination
exceeding the dirty limit and possibly strange OOM.
Reported-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Tested-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Reviewed-by: Neil Brown <neilb@suse.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
If we fail to prepare an anon_vma, the {new, old}_page should be released,
or they will leak.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit c9f01245 ("oom: remove oom_disable_count") has removed the
oom_disable_count counter which has been used for early break out from
oom_badness so we could never select a task with oom_score_adj set to
OOM_SCORE_ADJ_MIN (oom disabled).
Now that the counter is gone we are always going through heuristics
calculation and we always return a non zero positive value. This means
that we can end up killing a task with OOM disabled because it is
indistinguishable from regular tasks with 1% resp. CAP_SYS_ADMIN tasks
with 3% usage of memory or tasks with oom_score_adj set but OOM enabled.
Let's break out early if the task should have OOM disabled.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Lockdep reports there is potential deadlock for slub node list_lock.
discard_slab() is called with the lock hold in unfreeze_partials(),
which could trigger a slab allocation, which could hold the lock again.
discard_slab() doesn't need hold the lock actually, if the slab is
already removed from partial list.
Acked-by: Christoph Lameter <cl@linux.com>
Reported-and-tested-by: Yong Zhang <yong.zhang0@gmail.com>
Reported-and-tested-by: Julie Sullivan <kernelmail.jms@gmail.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
unfreeze_partials() needs add the page to partial list tail, since such page
hasn't too many free objects. We now explictly use DEACTIVATE_TO_TAIL for this,
while DEACTIVATE_TO_TAIL != 1. This will cause performance regression (eg, more
lock contention in node->list_lock) without below fix.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
bdi_prune_sb() in bdi_unregister() attempts to removes the bdi links
from all super_blocks and then del_timer_sync() the writeback timer.
However, this can race with __mark_inode_dirty(), leading to
bdi_wakeup_thread_delayed() rearming the writeback timer on the bdi
we're unregistering, after we've called del_timer_sync().
This can end up with the bdi being freed with an active timer inside it,
as in the case of the following dump after the removal of an SD card.
Fix this by redoing the del_timer_sync() in bdi_destory().
------------[ cut here ]------------
WARNING: at /home/rabin/kernel/arm/lib/debugobjects.c:262 debug_print_object+0x9c/0xc8()
ODEBUG: free active (active state 0) object type: timer_list hint: wakeup_timer_fn+0x0/0x180
Modules linked in:
Backtrace:
[<c00109dc>] (dump_backtrace+0x0/0x110) from [<c0236e4c>] (dump_stack+0x18/0x1c)
r6:c02bc638 r5:00000106 r4:c79f5d18 r3:00000000
[<c0236e34>] (dump_stack+0x0/0x1c) from [<c0025e6c>] (warn_slowpath_common+0x54/0x6c)
[<c0025e18>] (warn_slowpath_common+0x0/0x6c) from [<c0025f28>] (warn_slowpath_fmt+0x38/0x40)
r8:20000013 r7:c780c6f0 r6:c031613c r5:c780c6f0 r4:c02b1b29
r3:00000009
[<c0025ef0>] (warn_slowpath_fmt+0x0/0x40) from [<c015eb4c>] (debug_print_object+0x9c/0xc8)
r3:c02b1b29 r2:c02bc662
[<c015eab0>] (debug_print_object+0x0/0xc8) from [<c015f574>] (debug_check_no_obj_freed+0xac/0x1dc)
r6:c7964000 r5:00000001 r4:c7964000
[<c015f4c8>] (debug_check_no_obj_freed+0x0/0x1dc) from [<c00a9e38>] (kmem_cache_free+0x88/0x1f8)
[<c00a9db0>] (kmem_cache_free+0x0/0x1f8) from [<c014286c>] (blk_release_queue+0x70/0x78)
[<c01427fc>] (blk_release_queue+0x0/0x78) from [<c015290c>] (kobject_release+0x70/0x84)
r5:c79641f0 r4:c796420c
[<c015289c>] (kobject_release+0x0/0x84) from [<c0153ce4>] (kref_put+0x68/0x80)
r7:00000083 r6:c74083d0 r5:c015289c r4:c796420c
[<c0153c7c>] (kref_put+0x0/0x80) from [<c01527d0>] (kobject_put+0x48/0x5c)
r5:c79643b4 r4:c79641f0
[<c0152788>] (kobject_put+0x0/0x5c) from [<c013ddd8>] (blk_cleanup_queue+0x68/0x74)
r4:c7964000
[<c013dd70>] (blk_cleanup_queue+0x0/0x74) from [<c01a6370>] (mmc_blk_put+0x78/0xe8)
r5:00000000 r4:c794c400
[<c01a62f8>] (mmc_blk_put+0x0/0xe8) from [<c01a64b4>] (mmc_blk_release+0x24/0x38)
r5:c794c400 r4:c0322824
[<c01a6490>] (mmc_blk_release+0x0/0x38) from [<c00de11c>] (__blkdev_put+0xe8/0x170)
r5:c78d5e00 r4:c74083c0
[<c00de034>] (__blkdev_put+0x0/0x170) from [<c00de2c0>] (blkdev_put+0x11c/0x12c)
r8:c79f5f70 r7:00000001 r6:c74083d0 r5:00000083 r4:c74083c0
r3:00000000
[<c00de1a4>] (blkdev_put+0x0/0x12c) from [<c00b0724>] (kill_block_super+0x60/0x6c)
r7:c7942300 r6:c79f4000 r5:00000083 r4:c74083c0
[<c00b06c4>] (kill_block_super+0x0/0x6c) from [<c00b0a94>] (deactivate_locked_super+0x44/0x70)
r6:c79f4000 r5:c031af64 r4:c794dc00 r3:c00b06c4
[<c00b0a50>] (deactivate_locked_super+0x0/0x70) from [<c00b1358>] (deactivate_super+0x6c/0x70)
r5:c794dc00 r4:c794dc00
[<c00b12ec>] (deactivate_super+0x0/0x70) from [<c00c88b0>] (mntput_no_expire+0x188/0x194)
r5:c794dc00 r4:c7942300
[<c00c8728>] (mntput_no_expire+0x0/0x194) from [<c00c95e0>] (sys_umount+0x2e4/0x310)
r6:c7942300 r5:00000000 r4:00000000 r3:00000000
[<c00c92fc>] (sys_umount+0x0/0x310) from [<c000d940>] (ret_fast_syscall+0x0/0x30)
---[ end trace e5c83c92ada51c76 ]---
Cc: stable@kernel.org
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In balance_dirty_pages() task_ratelimit may be not initialized
(initialization skiped by goto pause), and then used when calling
tracing hook.
Fix it by moving the task_ratelimit assignment before goto pause.
Reported-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
Revert "tracing: Include module.h in define_trace.h"
irq: don't put module.h into irq.h for tracking irqgen modules.
bluetooth: macroize two small inlines to avoid module.h
ip_vs.h: fix implicit use of module_get/module_put from module.h
nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
include: replace linux/module.h with "struct module" wherever possible
include: convert various register fcns to macros to avoid include chaining
crypto.h: remove unused crypto_tfm_alg_modname() inline
uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
pm_runtime.h: explicitly requires notifier.h
linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
miscdevice.h: fix up implicit use of lists and types
stop_machine.h: fix implicit use of smp.h for smp_processor_id
of: fix implicit use of errno.h in include/linux/of.h
of_platform.h: delete needless include <linux/module.h>
acpi: remove module.h include from platform/aclinux.h
miscdevice.h: delete unnecessary inclusion of module.h
device_cgroup.h: delete needless include <linux/module.h>
net: sch_generic remove redundant use of <linux/module.h>
net: inet_timewait_sock doesnt need <linux/module.h>
...
Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in
- drivers/media/dvb/frontends/dibx000_common.c
- drivers/media/video/{mt9m111.c,ov6650.c}
- drivers/mfd/ab3550-core.c
- include/linux/dmaengine.h
* 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: Add a 'reason' to wb_writeback_work
writeback: send work item to queue_io, move_expired_inodes
writeback: trace event balance_dirty_pages
writeback: trace event bdi_dirty_ratelimit
writeback: fix ppc compile warnings on do_div(long long, unsigned long)
writeback: per-bdi background threshold
writeback: dirty position control - bdi reserve area
writeback: control dirty pause time
writeback: limit max dirty pause time
writeback: IO-less balance_dirty_pages()
writeback: per task dirty rate limit
writeback: stabilize bdi->dirty_ratelimit
writeback: dirty rate control
writeback: add bg_threshold parameter to __bdi_update_bandwidth()
writeback: dirty position control
writeback: account per-bdi accumulated dirtied pages
* 'for-3.2/core' of git://git.kernel.dk/linux-block: (29 commits)
block: don't call blk_drain_queue() if elevator is not up
blk-throttle: use queue_is_locked() instead of lockdep_is_held()
blk-throttle: Take blkcg->lock while traversing blkcg->policy_list
blk-throttle: Free up policy node associated with deleted rule
block: warn if tag is greater than real_max_depth.
block: make gendisk hold a reference to its queue
blk-flush: move the queue kick into
blk-flush: fix invalid BUG_ON in blk_insert_flush
block: Remove the control of complete cpu from bio.
block: fix a typo in the blk-cgroup.h file
block: initialize the bounce pool if high memory may be added later
block: fix request_queue lifetime handling by making blk_queue_cleanup() properly shutdown
block: drop @tsk from attempt_plug_merge() and explain sync rules
block: make get_request[_wait]() fail if queue is dead
block: reorganize throtl_get_tg() and blk_throtl_bio()
block: reorganize queue draining
block: drop unnecessary blk_get/put_queue() in scsi_cmd_ioctl() and blk_get_tg()
block: pass around REQ_* flags instead of broken down booleans during request alloc/free
block: move blk_throtl prototypes to block/blk.h
block: fix genhd refcounting in blkio_policy_parse_and_set()
...
Fix up trivial conflicts due to "mddev_t" -> "struct mddev" conversion
and making the request functions be of type "void" instead of "int" in
- drivers/md/{faulty.c,linear.c,md.c,md.h,multipath.c,raid0.c,raid1.c,raid10.c,raid5.c}
- drivers/staging/zram/zram_drv.c
Says Andrew:
"60 patches. That's good enough for -rc1 I guess. I have quite a lot
of detritus to be rechecked, work through maintainers, etc.
- most of the remains of MM
- rtc
- various misc
- cgroups
- memcg
- cpusets
- procfs
- ipc
- rapidio
- sysctl
- pps
- w1
- drivers/misc
- aio"
* akpm: (60 commits)
memcg: replace ss->id_lock with a rwlock
aio: allocate kiocbs in batches
drivers/misc/vmw_balloon.c: fix typo in code comment
drivers/misc/vmw_balloon.c: determine page allocation flag can_sleep outside loop
w1: disable irqs in critical section
drivers/w1/w1_int.c: multiple masters used same init_name
drivers/power/ds2780_battery.c: fix deadlock upon insertion and removal
drivers/power/ds2780_battery.c: add a nolock function to w1 interface
drivers/power/ds2780_battery.c: create central point for calling w1 interface
w1: ds2760 and ds2780, use ida for id and ida_simple_get() to get it
pps gpio client: add missing dependency
pps: new client driver using GPIO
pps: default echo function
include/linux/dma-mapping.h: add dma_zalloc_coherent()
sysctl: make CONFIG_SYSCTL_SYSCALL default to n
sysctl: add support for poll()
RapidIO: documentation update
drivers/net/rionet.c: fix ethernet address macros for LE platforms
RapidIO: fix potential null deref in rio_setup_device()
RapidIO: add mport driver for Tsi721 bridge
...
warning: symbol 'swap_cgroup_ctrl' was not declared. Should it be static?
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Various code in memcontrol.c () calls this_cpu_read() on the calculations
to be done from two different percpu variables, or does an open-coded
read-modify-write on a single percpu variable.
Disable preemption throughout these operations so that the writes go to
the correct palces.
[hannes@cmpxchg.org: added this_cpu to __this_cpu conversion]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a potential race between a thread charging a page and another
thread putting it back to the LRU list:
charge: putback:
SetPageCgroupUsed SetPageLRU
PageLRU && add to memcg LRU PageCgroupUsed && add to memcg LRU
The order of setting one flag and checking the other is crucial, otherwise
the charge may observe !PageLRU while the putback observes !PageCgroupUsed
and the page is not linked to the memcg LRU at all.
Global memory pressure may fix this by trying to isolate and putback the
page for reclaim, where that putback would link it to the memcg LRU again.
Without that, the memory cgroup is undeletable due to a charge whose
physical page can not be found and moved out.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Cc: Ying Han <yinghan@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reclaim decides to skip scanning an active list when the corresponding
inactive list is above a certain size in comparison to leave the assumed
working set alone while there are still enough reclaim candidates around.
The memcg implementation of comparing those lists instead reports whether
the whole memcg is low on the requested type of inactive pages,
considering all nodes and zones.
This can lead to an oversized active list not being scanned because of the
state of the other lists in the memcg, as well as an active list being
scanned while its corresponding inactive list has enough pages.
Not only is this wrong, it's also a scalability hazard, because the global
memory state over all nodes and zones has to be gathered for each memcg
and zone scanned.
Make these calculations purely based on the size of the two LRU lists
that are actually affected by the outcome of the decision.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If somebody is touching data too early, it might be easier to diagnose a
problem when dereferencing NULL at mem->info.nodeinfo[node] than trying to
understand why mem_cgroup_per_zone is [un|partly]initialized.
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before calling schedule_timeout(), task state should be changed.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The memcg code sometimes uses "struct mem_cgroup *mem" and sometimes uses
"struct mem_cgroup *memcg". Rename all mem variables to memcg in source
file.
Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the cgroup base was allocated with kmalloc, it was necessary to
annotate the variable with kmemleak_not_leak(). But because it has
recently been changed to be allocated with alloc_page() (which skips
kmemleak checks) causes a warning on boot up.
I was triggering this output:
allocated 8388608 bytes of page_cgroup
please try 'cgroup_disable=memory' option if you don't want memory cgroups
kmemleak: Trying to color unknown object at 0xf5840000 as Grey
Pid: 0, comm: swapper Not tainted 3.0.0-test #12
Call Trace:
[<c17e34e6>] ? printk+0x1d/0x1f^M
[<c10e2941>] paint_ptr+0x4f/0x78
[<c178ab57>] kmemleak_not_leak+0x58/0x7d
[<c108ae9f>] ? __rcu_read_unlock+0x9/0x7d
[<c1cdb462>] kmemleak_init+0x19d/0x1e9
[<c1cbf771>] start_kernel+0x346/0x3ec
[<c1cbf1b4>] ? loglevel+0x18/0x18
[<c1cbf0aa>] i386_start_kernel+0xaa/0xb0
After a bit of debugging I tracked the object 0xf840000 (and others) down
to the cgroup code. The change from allocating base with kmalloc to
alloc_page() has the base not calling kmemleak_alloc() which adds the
pointer to the object_tree_root, but kmemleak_not_leak() adds it to the
crt_early_log[] table. On kmemleak_init(), the entry is found in the
early_log[] but not the object_tree_root, and this error message is
displayed.
If alloc_page() fails then it defaults back to vmalloc() which still uses
the kmemleak_alloc() which makes us still need the kmemleak_not_leak()
call. The solution is to call the kmemleak_alloc() directly if the
alloc_page() succeeds.
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michel while working on the working set estimation code, noticed that
calling get_page_unless_zero() on a random pfn_to_page(random_pfn)
wasn't safe, if the pfn ended up being a tail page of a transparent
hugepage under splitting by __split_huge_page_refcount().
He then found the problem could also theoretically materialize with
page_cache_get_speculative() during the speculative radix tree lookups
that uses get_page_unless_zero() in SMP if the radix tree page is freed
and reallocated and get_user_pages is called on it before
page_cache_get_speculative has a chance to call get_page_unless_zero().
So the best way to fix the problem is to keep page_tail->_count zero at
all times. This will guarantee that get_page_unless_zero() can never
succeed on any tail page. page_tail->_mapcount is guaranteed zero and
is unused for all tail pages of a compound page, so we can simply
account the tail page references there and transfer them to
tail_page->_count in __split_huge_page_refcount() (in addition to the
head_page->_mapcount).
While debugging this s/_count/_mapcount/ change I also noticed get_page is
called by direct-io.c on pages returned by get_user_pages. That wasn't
entirely safe because the two atomic_inc in get_page weren't atomic. As
opposed to other get_user_page users like secondary-MMU page fault to
establish the shadow pagetables would never call any superflous get_page
after get_user_page returns. It's safer to make get_page universally safe
for tail pages and to use get_page_foll() within follow_page (inside
get_user_pages()). get_page_foll() is safe to do the refcounting for tail
pages without taking any locks because it is run within PT lock protected
critical sections (PT lock for pte and page_table_lock for
pmd_trans_huge).
The standard get_page() as invoked by direct-io instead will now take
the compound_lock but still only for tail pages. The direct-io paths
are usually I/O bound and the compound_lock is per THP so very
finegrined, so there's no risk of scalability issues with it. A simple
direct-io benchmarks with all lockdep prove locking and spinlock
debugging infrastructure enabled shows identical performance and no
overhead. So it's worth it. Ideally direct-io should stop calling
get_page() on pages returned by get_user_pages(). The spinlock in
get_page() is already optimized away for no-THP builds but doing
get_page() on tail pages returned by GUP is generally a rare operation
and usually only run in I/O paths.
This new refcounting on page_tail->_mapcount in addition to avoiding new
RCU critical sections will also allow the working set estimation code to
work without any further complexity associated to the tail page
refcounting with THP.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace direct i_nlink updates with the respective updater function
(inc_nlink, drop_nlink, clear_nlink, inode_dec_link_count).
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Avoid false sharing of the vm_stat array.
This was found to adversely affect tmpfs I/O performance.
Tests run on a 640 cpu UV system.
With 120 threads doing parallel writes, each to different tmpfs mounts:
No patch: ~300 MB/sec
With vm_stat alignment: ~430 MB/sec
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Acked-by: Christoph Lameter <cl@gentwo.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A process spent 30 minutes exiting, just munlocking the pages of a large
anonymous area that had been alternately mprotected into page-sized vmas:
for every single page there's an anon_vma walk through all the other
little vmas to find the right one.
A general fix to that would be a lot more complicated (use prio_tree on
anon_vma?), but there's one very simple thing we can do to speed up the
common case: if a page to be munlocked is mapped only once, then it is our
vma that it is mapped into, and there's no need whatever to walk through
all the others.
Okay, there is a very remote race in munlock_vma_pages_range(), if between
its follow_page() and lock_page(), another process were to munlock the
same page, then page reclaim remove it from our vma, then another process
mlock it again. We would find it with page_mapcount 1, yet it's still
mlocked in another process. But never mind, that's much less likely than
the down_read_trylock() failure which munlocking already tolerates (in
try_to_unmap_one()): in due course page reclaim will discover and move the
page to unevictable instead.
[akpm@linux-foundation.org: add comment]
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are three cases of update_mmu_cache() in the file, and the case in
function collapse_huge_page() has a typo, namely the last parameter used,
which is corrected based on the other two cases.
Due to the define of update_mmu_cache by X86, the only arch that
implements THP currently, the change here has no really crystal point, but
one or two minutes of efforts could be saved for those archs that are
likely to support THP in future.
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The THP copy-on-write handler falls back to regular-sized pages for a huge
page replacement upon allocation failure or if THP has been individually
disabled in the target VMA. The loop responsible for copying page-sized
chunks accidentally uses multiples of PAGE_SHIFT instead of PAGE_SIZE as
the virtual address arg for copy_user_highpage().
Signed-off-by: Hillf Danton <dhillf@gmail.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MCL_FUTURE does not move pages between lru list and draining the LRU per
cpu pagevecs is a nasty activity. Avoid doing it unecessarily.
Signed-off-by: Christoph Lameter <cl@gentwo.org>
Cc: David Rientjes <rientjes@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If compaction can proceed, shrink_zones() stops doing any work but its
callers still call shrink_slab() which raises the priority and potentially
sleeps. This is unnecessary and wasteful so this patch aborts direct
reclaim/compaction entirely if compaction can proceed.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When suffering from memory fragmentation due to unfreeable pages, THP page
faults will repeatedly try to compact memory. Due to the unfreeable
pages, compaction fails.
Needless to say, at that point page reclaim also fails to create free
contiguous 2MB areas. However, that doesn't stop the current code from
trying, over and over again, and freeing a minimum of 4MB (2UL <<
sc->order pages) at every single invocation.
This resulted in my 12GB system having 2-3GB free memory, a corresponding
amount of used swap and very sluggish response times.
This can be avoided by having the direct reclaim code not reclaim from
zones that already have plenty of free memory available for compaction.
If compaction still fails due to unmovable memory, doing additional
reclaim will only hurt the system, not help.
[jweiner@redhat.com: change comment to explain the order check]
Signed-off-by: Rik van Riel <riel@redhat.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a race between putback_lru_page() and shmem_lock with lock=0 happens,
progrom execution order is as follows, but clear_bit in processor #1 could
be reordered right before spin_unlock of processor #1. Then, the page
would be stranded on the unevictable list.
spin_lock
SetPageLRU
spin_unlock
clear_bit(AS_UNEVICTABLE)
spin_lock
if PageLRU()
if !test_bit(AS_UNEVICTABLE)
move evictable list
smp_mb
if !test_bit(AS_UNEVICTABLE)
move evictable list
spin_unlock
But, pagevec_lookup() in scan_mapping_unevictable_pages() has
rcu_read_[un]lock() so it could protect reordering before reaching
test_bit(AS_UNEVICTABLE) on processor #1 so this problem never happens.
But it's a unexpected side effect and we should solve this problem
properly.
This patch adds a barrier after mapping_clear_unevictable.
I didn't meet this problem but just found during review.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Quiet the sparse noise:
warning: symbol 'khugepaged_scan' was not declared. Should it be static?
warning: context imbalance in 'khugepaged_scan_mm_slot' - unexpected unlock
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Quiet the spares noise:
warning: symbol 'default_policy' was not declared. Should it be static?
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stephen Wilson <wilsons@start.ca>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Quiet the following sparse noise:
warning: symbol 'swap_token_memcg' was not declared. Should it be static?
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Quiet the following sparse noise in this file:
warning: symbol 'memblock_overlaps_region' was not declared. Should it be static?
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers,com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Tomi Valkeinen <tomi.valkeinen@nokia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At one point, anonymous pages were supposed to go on the unevictable list
when no swap space was configured, and the idea was to manually rescue
those pages after adding swap and making them evictable again. But
nowadays, swap-backed pages on the anon LRU list are not scanned without
available swap space anyway, so there is no point in moving them to a
separate list anymore.
The manual rescue could also be used in case pages were stranded on the
unevictable list due to race conditions. But the code has been around for
a while now and newly discovered bugs should be properly reported and
dealt with instead of relying on such a manual fixup.
In addition to the lack of a usecase, the sysfs interface to rescue pages
from a specific NUMA node has been broken since its introduction, so it's
unlikely that anybody ever relied on that.
This patch removes the functionality behind the sysctl and the
node-interface and emits a one-time warning when somebody tries to access
either of them.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reported-by: Kautuk Consul <consul.kautuk@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
write_scan_unevictable_node() checks the value req returned by
strict_strtoul() and returns 1 if req is 0.
However, when strict_strtoul() returns 0, it means successful conversion
of buf to unsigned long.
Due to this, the function was not proceeding to scan the zones for
unevictable pages even though we write a valid value to the
scan_unevictable_pages sys file.
Change this check slightly to check for invalid value in buf as well as 0
value stored in res after successful conversion via strict_strtoul. In
both cases, we do not perform the scanning of this node's zones.
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There's no compact_zone_order() user outside file scope, so make it static.
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit fb46e73520 ("HWPOISON: Convert pr_debugs to pr_info) authored
by Andi Kleen converted a number of pr_debug()s to pr_info()s.
About the same time additional code with pr_debug()s was added by two
other commits 8c6c2ecb44 ("HWPOSION, hugetlb: recover from free hugepage
error when !MF_COUNT_INCREASED") and d950b95882 ("HWPOISON, hugetlb:
soft offlining for hugepage"). And these pr_debug()s failed to get
converted to pr_info()s.
This patch converts them as well. And does some minor related whitespace
cleanup.
Signed-off-by: Dean Nelson <dnelson@redhat.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ret variable is really not needed in mm_take_all_locks().
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some vmalloc failure paths do not report OOM conditions.
Add warn_alloc_failed, which also does a dump_stack, to those failure
paths.
This allows more site specific vmalloc failure logging message printks to
be removed.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There 2 places to read pgdat in kswapd. One is return from a successful
balance, another is waked up from kswapd sleeping. The new_order and
new_classzone_idx represent the balance input order and classzone_idx.
But current new_order and new_classzone_idx are not assigned after
kswapd_try_to_sleep(), that will cause a bug in the following scenario.
1: after a successful balance, kswapd goes to sleep, and new_order = 0;
new_classzone_idx = __MAX_NR_ZONES - 1;
2: kswapd waked up with order = 3 and classzone_idx = ZONE_NORMAL
3: in the balance_pgdat() running, a new balance wakeup happened with
order = 5, and classzone_idx = ZONE_NORMAL
4: the first wakeup(order = 3) finished successufly, return order = 3
but, the new_order is still 0, so, this balancing will be treated as a
failed balance. And then the second tighter balancing will be missed.
So, to avoid the above problem, the new_order and new_classzone_idx need
to be assigned for later successful comparison.
Signed-off-by: Alex Shi <alex.shi@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Tested-by: Pádraig Brady <P@draigBrady.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
warning: function 'memblock_memory_can_coalesce'
with external linkage has definition.
Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit 215ddd66 ("mm: vmscan: only read new_classzone_idx from pgdat
when reclaiming successfully") , Mel Gorman said kswapd is better to sleep
after a unsuccessful balancing if there is tighter reclaim request pending
in the balancing. But in the following scenario, kswapd do something that
is not matched our expectation. The patch fixes this issue.
1, Read pgdat request A (classzone_idx, order = 3)
2, balance_pgdat()
3, During pgdat, a new pgdat request B (classzone_idx, order = 5) is placed
4, balance_pgdat() returns but failed since returned order = 0
5, pgdat of request A assigned to balance_pgdat(), and do balancing again.
While the expectation behavior of kswapd should try to sleep.
Signed-off-by: Alex Shi <alex.shi@intel.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Tested-by: Pádraig Brady <P@draigBrady.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds support for highmem pages poisoning and verification to the
debug-pagealloc feature for no-architecture support.
[akpm@linux-foundation.org: remove unneeded preempt_disable/enable]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add __attribute__((format (printf...) to the function to validate format
and arguments. Use vsprintf extension %pV to avoid any possible message
interleaving. Coalesce format string. Convert printks/pr_warning to
pr_warn.
[akpm@linux-foundation.org: use the __printf() macro]
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds THP support to mremap (decreases the number of split_huge_page()
calls).
Here are also some benchmarks with a proggy like this:
===
#define _GNU_SOURCE
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/time.h>
#define SIZE (5UL*1024*1024*1024)
int main()
{
static struct timeval oldstamp, newstamp;
long diffsec;
char *p, *p2, *p3, *p4;
if (posix_memalign((void **)&p, 2*1024*1024, SIZE))
perror("memalign"), exit(1);
if (posix_memalign((void **)&p2, 2*1024*1024, SIZE))
perror("memalign"), exit(1);
if (posix_memalign((void **)&p3, 2*1024*1024, 4096))
perror("memalign"), exit(1);
memset(p, 0xff, SIZE);
memset(p2, 0xff, SIZE);
memset(p3, 0x77, 4096);
gettimeofday(&oldstamp, NULL);
p4 = mremap(p, SIZE, SIZE, MREMAP_FIXED|MREMAP_MAYMOVE, p3);
gettimeofday(&newstamp, NULL);
diffsec = newstamp.tv_sec - oldstamp.tv_sec;
diffsec = newstamp.tv_usec - oldstamp.tv_usec + 1000000 * diffsec;
printf("usec %ld\n", diffsec);
if (p == MAP_FAILED || p4 != p3)
//if (p == MAP_FAILED)
perror("mremap"), exit(1);
if (memcmp(p4, p2, SIZE))
printf("mremap bug\n"), exit(1);
printf("ok\n");
return 0;
}
===
THP on
Performance counter stats for './largepage13' (3 runs):
69195836 dTLB-loads ( +- 3.546% ) (scaled from 50.30%)
60708 dTLB-load-misses ( +- 11.776% ) (scaled from 52.62%)
676266476 dTLB-stores ( +- 5.654% ) (scaled from 69.54%)
29856 dTLB-store-misses ( +- 4.081% ) (scaled from 89.22%)
1055848782 iTLB-loads ( +- 4.526% ) (scaled from 80.18%)
8689 iTLB-load-misses ( +- 2.987% ) (scaled from 58.20%)
7.314454164 seconds time elapsed ( +- 0.023% )
THP off
Performance counter stats for './largepage13' (3 runs):
1967379311 dTLB-loads ( +- 0.506% ) (scaled from 60.59%)
9238687 dTLB-load-misses ( +- 22.547% ) (scaled from 61.87%)
2014239444 dTLB-stores ( +- 0.692% ) (scaled from 60.40%)
3312335 dTLB-store-misses ( +- 7.304% ) (scaled from 67.60%)
6764372065 iTLB-loads ( +- 0.925% ) (scaled from 79.00%)
8202 iTLB-load-misses ( +- 0.475% ) (scaled from 70.55%)
9.693655243 seconds time elapsed ( +- 0.069% )
grep thp /proc/vmstat
thp_fault_alloc 35849
thp_fault_fallback 0
thp_collapse_alloc 3
thp_collapse_alloc_failed 0
thp_split 0
thp_split 0 confirms no thp split despite plenty of hugepages allocated.
The measurement of only the mremap time (so excluding the 3 long
memset and final long 10GB memory accessing memcmp):
THP on
usec 14824
usec 14862
usec 14859
THP off
usec 256416
usec 255981
usec 255847
With an older kernel without the mremap optimizations (the below patch
optimizes the non THP version too).
THP on
usec 392107
usec 390237
usec 404124
THP off
usec 444294
usec 445237
usec 445820
I guess with a threaded program that sends more IPI on large SMP it'd
create an even larger difference.
All debug options are off except DEBUG_VM to avoid skewing the
results.
The only problem for native 2M mremap like it happens above both the
source and destination address must be 2M aligned or the hugepmd can't be
moved without a split but that is an hardware limitation.
[akpm@linux-foundation.org: coding-style nitpicking]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This replaces ptep_clear_flush() with ptep_get_and_clear() and a single
flush_tlb_range() at the end of the loop, to avoid sending one IPI for
each page.
The mmu_notifier_invalidate_range_start/end section is enlarged
accordingly but this is not going to fundamentally change things. It was
more by accident that the region under mremap was for the most part still
available for secondary MMUs: the primary MMU was never allowed to
reliably access that region for the duration of the mremap (modulo
trapping SIGSEGV on the old address range which sounds unpractical and
flakey). If users wants secondary MMUs not to lose access to a large
region under mremap they should reduce the mremap size accordingly in
userland and run multiple calls. Overall this will run faster so it's
actually going to reduce the time the region is under mremap for the
primary MMU which should provide a net benefit to apps.
For KVM this is a noop because the guest physical memory is never
mremapped, there's just no point it ever moving it while guest runs. One
target of this optimization is JVM GC (so unrelated to the mmu notifier
logic).
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Using "- 1" relies on the old_end to be page aligned and PAGE_SIZE > 1,
those are reasonable requirements but the check remains obscure and it
looks more like an off by one error than an overflow check. This I feel
will improve readability.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the NO_BOOTMEM symbol added architectures may now use the following
syntax to tell that they do not need bootmem:
select NO_BOOTMEM
This is much more convinient than adding a new kconfig symbol which was
otherwise required.
Adding this symbol does not conflict with the architctures that already
define their own symbol.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SPARC32 require access to the start address. Add a new helper
memblock_start_of_DRAM() to give access to the address of the first
memblock - which contains the lowest address.
The awkward name was chosen to match the already present
memblock_end_of_DRAM().
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The /proc/vmallocinfo shows information about vmalloc allocations in
vmlist that is a linklist of vm_struct. It, however, may access pages
field of vm_struct where a page was not allocated. This results in a null
pointer access and leads to a kernel panic.
Why this happens: In __vmalloc_node_range() called from vmalloc(), newly
allocated vm_struct is added to vmlist at __get_vm_area_node() and then,
some fields of vm_struct such as nr_pages and pages are set at
__vmalloc_area_node(). In other words, it is added to vmlist before it is
fully initialized. At the same time, when the /proc/vmallocinfo is read,
it accesses the pages field of vm_struct according to the nr_pages field
at show_numa_info(). Thus, a null pointer access happens.
The patch adds the newly allocated vm_struct to the vmlist *after* it is
fully initialized. So, it can avoid accessing the pages field with
unallocated page when show_numa_info() is called.
Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: <stable@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use newly introduced memchr_inv() for page verification.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
memchr_inv() is mainly used to check whether the whole buffer is filled
with just a specified byte.
The function name and prototype are stolen from logfs and the
implementation is from SLUB.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Acked-by: Joern Engel <joern@logfs.org>
Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
printk_ratelimit() should not be used, because it shares ratelimiting
state with all other unrelated printk_ratelimit() callsites.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's possible a zone watermark is ok when entering the balance_pgdat()
loop, while the zone is within the requested classzone_idx. Count pages
from this zone into `balanced'. In this way, we can skip shrinking zones
too much for high order allocation.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When direct reclaim encounters a dirty page, it gets recycled around the
LRU for another cycle. This patch marks the page PageReclaim similar to
deactivate_page() so that the page gets reclaimed almost immediately after
the page gets cleaned. This is to avoid reclaiming clean pages that are
younger than a dirty page encountered at the end of the LRU that might
have been something like a use-once page.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Alex Elder <aelder@sgi.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Workloads that are allocating frequently and writing files place a large
number of dirty pages on the LRU. With use-once logic, it is possible for
them to reach the end of the LRU quickly requiring the reclaimer to scan
more to find clean pages. Ordinarily, processes that are dirtying memory
will get throttled by dirty balancing but this is a global heuristic and
does not take into account that LRUs are maintained on a per-zone basis.
This can lead to a situation whereby reclaim is scanning heavily, skipping
over a large number of pages under writeback and recycling them around the
LRU consuming CPU.
This patch checks how many of the number of pages isolated from the LRU
were dirty and under writeback. If a percentage of them under writeback,
the process will be throttled if a backing device or the zone is
congested. Note that this applies whether it is anonymous or file-backed
pages that are under writeback meaning that swapping is potentially
throttled. This is intentional due to the fact if the swap device is
congested, scanning more pages and dispatching more IO is not going to
help matters.
The percentage that must be in writeback depends on the priority. At
default priority, all of them must be dirty. At DEF_PRIORITY-1, 50% of
them must be, DEF_PRIORITY-2, 25% etc. i.e. as pressure increases the
greater the likelihood the process will get throttled to allow the flusher
threads to make some progress.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Johannes Weiner <jweiner@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Alex Elder <aelder@sgi.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It is preferable that no dirty pages are dispatched for cleaning from the
page reclaim path. At normal priorities, this patch prevents kswapd
writing pages.
However, page reclaim does have a requirement that pages be freed in a
particular zone. If it is failing to make sufficient progress (reclaiming
< SWAP_CLUSTER_MAX at any priority priority), the priority is raised to
scan more pages. A priority of DEF_PRIORITY - 3 is considered to be the
point where kswapd is getting into trouble reclaiming pages. If this
priority is reached, kswapd will dispatch pages for writing.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Alex Elder <aelder@sgi.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Lumpy reclaim worked with two passes - the first which queued pages for IO
and the second which waited on writeback. As direct reclaim can no longer
write pages there is some dead code. This patch removes it but direct
reclaim will continue to wait on pages under writeback while in
synchronous reclaim mode.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Alex Elder <aelder@sgi.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Testing from the XFS folk revealed that there is still too much I/O from
the end of the LRU in kswapd. Previously it was considered acceptable by
VM people for a small number of pages to be written back from reclaim with
testing generally showing about 0.3% of pages reclaimed were written back
(higher if memory was low). That writing back a small number of pages is
ok has been heavily disputed for quite some time and Dave Chinner
explained it well;
It doesn't have to be a very high number to be a problem. IO
is orders of magnitude slower than the CPU time it takes to
flush a page, so the cost of making a bad flush decision is
very high. And single page writeback from the LRU is almost
always a bad flush decision.
To complicate matters, filesystems respond very differently to requests
from reclaim according to Christoph Hellwig;
xfs tries to write it back if the requester is kswapd
ext4 ignores the request if it's a delayed allocation
btrfs ignores the request
As a result, each filesystem has different performance characteristics
when under memory pressure and there are many pages being dirtied. In
some cases, the request is ignored entirely so the VM cannot depend on the
IO being dispatched.
The objective of this series is to reduce writing of filesystem-backed
pages from reclaim, play nicely with writeback that is already in progress
and throttle reclaim appropriately when writeback pages are encountered.
The assumption is that the flushers will always write pages faster than if
reclaim issues the IO.
A secondary goal is to avoid the problem whereby direct reclaim splices
two potentially deep call stacks together.
There is a potential new problem as reclaim has less control over how long
before a page in a particularly zone or container is cleaned and direct
reclaimers depend on kswapd or flusher threads to do the necessary work.
However, as filesystems sometimes ignore direct reclaim requests already,
it is not expected to be a serious issue.
Patch 1 disables writeback of filesystem pages from direct reclaim
entirely. Anonymous pages are still written.
Patch 2 removes dead code in lumpy reclaim as it is no longer able
to synchronously write pages. This hurts lumpy reclaim but
there is an expectation that compaction is used for hugepage
allocations these days and lumpy reclaim's days are numbered.
Patches 3-4 add warnings to XFS and ext4 if called from
direct reclaim. With patch 1, this "never happens" and is
intended to catch regressions in this logic in the future.
Patch 5 disables writeback of filesystem pages from kswapd unless
the priority is raised to the point where kswapd is considered
to be in trouble.
Patch 6 throttles reclaimers if too many dirty pages are being
encountered and the zones or backing devices are congested.
Patch 7 invalidates dirty pages found at the end of the LRU so they
are reclaimed quickly after being written back rather than
waiting for a reclaimer to find them
I consider this series to be orthogonal to the writeback work but it is
worth noting that the writeback work affects the viability of patch 8 in
particular.
I tested this on ext4 and xfs using fs_mark, a simple writeback test based
on dd and a micro benchmark that does a streaming write to a large mapping
(exercises use-once LRU logic) followed by streaming writes to a mix of
anonymous and file-backed mappings. The command line for fs_mark when
botted with 512M looked something like
./fs_mark -d /tmp/fsmark-2676 -D 100 -N 150 -n 150 -L 25 -t 1 -S0 -s 10485760
The number of files was adjusted depending on the amount of available
memory so that the files created was about 3xRAM. For multiple threads,
the -d switch is specified multiple times.
The test machine is x86-64 with an older generation of AMD processor with
4 cores. The underlying storage was 4 disks configured as RAID-0 as this
was the best configuration of storage I had available. Swap is on a
separate disk. Dirty ratio was tuned to 40% instead of the default of
20%.
Testing was run with and without monitors to both verify that the patches
were operating as expected and that any performance gain was real and not
due to interference from monitors.
Here is a summary of results based on testing XFS.
512M1P-xfs Files/s mean 32.69 ( 0.00%) 34.44 ( 5.08%)
512M1P-xfs Elapsed Time fsmark 51.41 48.29
512M1P-xfs Elapsed Time simple-wb 114.09 108.61
512M1P-xfs Elapsed Time mmap-strm 113.46 109.34
512M1P-xfs Kswapd efficiency fsmark 62% 63%
512M1P-xfs Kswapd efficiency simple-wb 56% 61%
512M1P-xfs Kswapd efficiency mmap-strm 44% 42%
512M-xfs Files/s mean 30.78 ( 0.00%) 35.94 (14.36%)
512M-xfs Elapsed Time fsmark 56.08 48.90
512M-xfs Elapsed Time simple-wb 112.22 98.13
512M-xfs Elapsed Time mmap-strm 219.15 196.67
512M-xfs Kswapd efficiency fsmark 54% 56%
512M-xfs Kswapd efficiency simple-wb 54% 55%
512M-xfs Kswapd efficiency mmap-strm 45% 44%
512M-4X-xfs Files/s mean 30.31 ( 0.00%) 33.33 ( 9.06%)
512M-4X-xfs Elapsed Time fsmark 63.26 55.88
512M-4X-xfs Elapsed Time simple-wb 100.90 90.25
512M-4X-xfs Elapsed Time mmap-strm 261.73 255.38
512M-4X-xfs Kswapd efficiency fsmark 49% 50%
512M-4X-xfs Kswapd efficiency simple-wb 54% 56%
512M-4X-xfs Kswapd efficiency mmap-strm 37% 36%
512M-16X-xfs Files/s mean 60.89 ( 0.00%) 65.22 ( 6.64%)
512M-16X-xfs Elapsed Time fsmark 67.47 58.25
512M-16X-xfs Elapsed Time simple-wb 103.22 90.89
512M-16X-xfs Elapsed Time mmap-strm 237.09 198.82
512M-16X-xfs Kswapd efficiency fsmark 45% 46%
512M-16X-xfs Kswapd efficiency simple-wb 53% 55%
512M-16X-xfs Kswapd efficiency mmap-strm 33% 33%
Up until 512-4X, the FSmark improvements were statistically significant.
For the 4X and 16X tests the results were within standard deviations but
just barely. The time to completion for all tests is improved which is an
important result. In general, kswapd efficiency is not affected by
skipping dirty pages.
1024M1P-xfs Files/s mean 39.09 ( 0.00%) 41.15 ( 5.01%)
1024M1P-xfs Elapsed Time fsmark 84.14 80.41
1024M1P-xfs Elapsed Time simple-wb 210.77 184.78
1024M1P-xfs Elapsed Time mmap-strm 162.00 160.34
1024M1P-xfs Kswapd efficiency fsmark 69% 75%
1024M1P-xfs Kswapd efficiency simple-wb 71% 77%
1024M1P-xfs Kswapd efficiency mmap-strm 43% 44%
1024M-xfs Files/s mean 35.45 ( 0.00%) 37.00 ( 4.19%)
1024M-xfs Elapsed Time fsmark 94.59 91.00
1024M-xfs Elapsed Time simple-wb 229.84 195.08
1024M-xfs Elapsed Time mmap-strm 405.38 440.29
1024M-xfs Kswapd efficiency fsmark 79% 71%
1024M-xfs Kswapd efficiency simple-wb 74% 74%
1024M-xfs Kswapd efficiency mmap-strm 39% 42%
1024M-4X-xfs Files/s mean 32.63 ( 0.00%) 35.05 ( 6.90%)
1024M-4X-xfs Elapsed Time fsmark 103.33 97.74
1024M-4X-xfs Elapsed Time simple-wb 204.48 178.57
1024M-4X-xfs Elapsed Time mmap-strm 528.38 511.88
1024M-4X-xfs Kswapd efficiency fsmark 81% 70%
1024M-4X-xfs Kswapd efficiency simple-wb 73% 72%
1024M-4X-xfs Kswapd efficiency mmap-strm 39% 38%
1024M-16X-xfs Files/s mean 42.65 ( 0.00%) 42.97 ( 0.74%)
1024M-16X-xfs Elapsed Time fsmark 103.11 99.11
1024M-16X-xfs Elapsed Time simple-wb 200.83 178.24
1024M-16X-xfs Elapsed Time mmap-strm 397.35 459.82
1024M-16X-xfs Kswapd efficiency fsmark 84% 69%
1024M-16X-xfs Kswapd efficiency simple-wb 74% 73%
1024M-16X-xfs Kswapd efficiency mmap-strm 39% 40%
All FSMark tests up to 16X had statistically significant improvements.
For the most part, tests are completing faster with the exception of the
streaming writes to a mixture of anonymous and file-backed mappings which
were slower in two cases
In the cases where the mmap-strm tests were slower, there was more
swapping due to dirty pages being skipped. The number of additional pages
swapped is almost identical to the fewer number of pages written from
reclaim. In other words, roughly the same number of pages were reclaimed
but swapping was slower. As the test is a bit unrealistic and stresses
memory heavily, the small shift is acceptable.
4608M1P-xfs Files/s mean 29.75 ( 0.00%) 30.96 ( 3.91%)
4608M1P-xfs Elapsed Time fsmark 512.01 492.15
4608M1P-xfs Elapsed Time simple-wb 618.18 566.24
4608M1P-xfs Elapsed Time mmap-strm 488.05 465.07
4608M1P-xfs Kswapd efficiency fsmark 93% 86%
4608M1P-xfs Kswapd efficiency simple-wb 88% 84%
4608M1P-xfs Kswapd efficiency mmap-strm 46% 45%
4608M-xfs Files/s mean 27.60 ( 0.00%) 28.85 ( 4.33%)
4608M-xfs Elapsed Time fsmark 555.96 532.34
4608M-xfs Elapsed Time simple-wb 659.72 571.85
4608M-xfs Elapsed Time mmap-strm 1082.57 1146.38
4608M-xfs Kswapd efficiency fsmark 89% 91%
4608M-xfs Kswapd efficiency simple-wb 88% 82%
4608M-xfs Kswapd efficiency mmap-strm 48% 46%
4608M-4X-xfs Files/s mean 26.00 ( 0.00%) 27.47 ( 5.35%)
4608M-4X-xfs Elapsed Time fsmark 592.91 564.00
4608M-4X-xfs Elapsed Time simple-wb 616.65 575.07
4608M-4X-xfs Elapsed Time mmap-strm 1773.02 1631.53
4608M-4X-xfs Kswapd efficiency fsmark 90% 94%
4608M-4X-xfs Kswapd efficiency simple-wb 87% 82%
4608M-4X-xfs Kswapd efficiency mmap-strm 43% 43%
4608M-16X-xfs Files/s mean 26.07 ( 0.00%) 26.42 ( 1.32%)
4608M-16X-xfs Elapsed Time fsmark 602.69 585.78
4608M-16X-xfs Elapsed Time simple-wb 606.60 573.81
4608M-16X-xfs Elapsed Time mmap-strm 1549.75 1441.86
4608M-16X-xfs Kswapd efficiency fsmark 98% 98%
4608M-16X-xfs Kswapd efficiency simple-wb 88% 82%
4608M-16X-xfs Kswapd efficiency mmap-strm 44% 42%
Unlike the other tests, the fsmark results are not statistically
significant but the min and max times are both improved and for the most
part, tests completed faster.
There are other indications that this is an improvement as well. For
example, in the vast majority of cases, there were fewer pages scanned by
direct reclaim implying in many cases that stalls due to direct reclaim
are reduced. KSwapd is scanning more due to skipping dirty pages which is
unfortunate but the CPU usage is still acceptable
In an earlier set of tests, I used blktrace and in almost all cases
throughput throughout the entire test was higher. However, I ended up
discarding those results as recording blktrace data was too heavy for my
liking.
On a laptop, I plugged in a USB stick and ran a similar tests of tests
using it as backing storage. A desktop environment was running and for
the entire duration of the tests, firefox and gnome terminal were
launching and exiting to vaguely simulate a user.
1024M-xfs Files/s mean 0.41 ( 0.00%) 0.44 ( 6.82%)
1024M-xfs Elapsed Time fsmark 2053.52 1641.03
1024M-xfs Elapsed Time simple-wb 1229.53 768.05
1024M-xfs Elapsed Time mmap-strm 4126.44 4597.03
1024M-xfs Kswapd efficiency fsmark 84% 85%
1024M-xfs Kswapd efficiency simple-wb 92% 81%
1024M-xfs Kswapd efficiency mmap-strm 60% 51%
1024M-xfs Avg wait ms fsmark 5404.53 4473.87
1024M-xfs Avg wait ms simple-wb 2541.35 1453.54
1024M-xfs Avg wait ms mmap-strm 3400.25 3852.53
The mmap-strm results were hurt because firefox launching had a tendency
to push the test out of memory. On the postive side, firefox launched
marginally faster with the patches applied. Time to completion for many
tests was faster but more importantly - the "Avg wait" time as measured by
iostat was far lower implying the system would be more responsive. It was
also the case that "Avg wait ms" on the root filesystem was lower. I
tested it manually and while the system felt slightly more responsive
while copying data to a USB stick, it was marginal enough that it could be
my imagination.
This patch: do not writeback filesystem pages in direct reclaim.
When kswapd is failing to keep zones above the min watermark, a process
will enter direct reclaim in the same manner kswapd does. If a dirty page
is encountered during the scan, this page is written to backing storage
using mapping->writepage.
This causes two problems. First, it can result in very deep call stacks,
particularly if the target storage or filesystem are complex. Some
filesystems ignore write requests from direct reclaim as a result. The
second is that a single-page flush is inefficient in terms of IO. While
there is an expectation that the elevator will merge requests, this does
not always happen. Quoting Christoph Hellwig;
The elevator has a relatively small window it can operate on,
and can never fix up a bad large scale writeback pattern.
This patch prevents direct reclaim writing back filesystem pages by
checking if current is kswapd. Anonymous pages are still written to swap
as there is not the equivalent of a flusher thread for anonymous pages.
If the dirty pages cannot be written back, they are placed back on the LRU
lists. There is now a direct dependency on dirty page balancing to
prevent too many pages in the system being dirtied which would prevent
reclaim making forward progress.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Alex Elder <aelder@sgi.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The nr_force_scan[] tuple holds the effective scan numbers for anon and
file pages in case the situation called for a forced scan and the
regularly calculated scan numbers turned out zero.
However, the effective scan number can always be assumed to be
SWAP_CLUSTER_MAX right before the division into anon and file. The
numerators and denominator are properly set up for all cases, be it force
scan for just file, just anon, or both, to do the right thing.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When we get a bad_page bug report, it's useful to see what modules the
user had loaded.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
test_set_oom_score_adj() was introduced in 72788c3856 ("oom: replace
PF_OOM_ORIGIN with toggling oom_score_adj") to temporarily elevate
current's oom_score_adj for ksm and swapoff without requiring an
additional per-process flag.
Using that function to both set oom_score_adj to OOM_SCORE_ADJ_MAX and
then reinstate the previous value is racy since it's possible that
userspace can set the value to something else itself before the old value
is reinstated. That results in userspace setting current's oom_score_adj
to a different value and then the kernel immediately setting it back to
its previous value without notification.
To fix this, a new compare_swap_oom_score_adj() function is introduced
with the same semantics as the compare and swap CAS instruction, or
CMPXCHG on x86. It is used to reinstate the previous value of
oom_score_adj if and only if the present value is the same as the old
value.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This removes mm->oom_disable_count entirely since it's unnecessary and
currently buggy. The counter was intended to be per-process but it's
currently decremented in the exit path for each thread that exits, causing
it to underflow.
The count was originally intended to prevent oom killing threads that
share memory with threads that cannot be killed since it doesn't lead to
future memory freeing. The counter could be fixed to represent all
threads sharing the same mm, but it's better to remove the count since:
- it is possible that the OOM_DISABLE thread sharing memory with the
victim is waiting on that thread to exit and will actually cause
future memory freeing, and
- there is no guarantee that a thread is disabled from oom killing just
because another thread sharing its mm is oom disabled.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After selecting a task to kill, the oom killer iterates all processes and
kills all other threads that share the same mm_struct in different thread
groups. It would not otherwise be helpful to kill a thread if its memory
would not be subsequently freed.
A kernel thread, however, may assume a user thread's mm by using
use_mm(). This is only temporary and should not result in sending a
SIGKILL to that kthread.
This patch ensures that only user threads and not kthreads are sent a
SIGKILL if they share the same mm_struct as the oom killed task.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a thread has been oom killed and is frozen, thaw it before returning to
the page allocator. Otherwise, it can stay frozen indefinitely and no
memory will be freed.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Looks like someone got distracted after adding the comment characters.
Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
per-task block plug can reduce block queue lock contention and increase
request merge. Currently page reclaim doesn't support it. I originally
thought page reclaim doesn't need it, because kswapd thread count is
limited and file cache write is done at flusher mostly.
When I test a workload with heavy swap in a 4-node machine, each CPU is
doing direct page reclaim and swap. This causes block queue lock
contention. In my test, without below patch, the CPU utilization is about
2% ~ 7%. With the patch, the CPU utilization is about 1% ~ 3%. Disk
throughput isn't changed. This should improve normal kswapd write and
file cache write too (increase request merge for example), but might not
be so obvious as I explain above.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
unmap_and_move() is one a big messy function. Clean it up.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In __zone_reclaim case, we don't want to shrink mapped page. Nonetheless,
we have isolated mapped page and re-add it into LRU's head. It's
unnecessary CPU overhead and makes LRU churning.
Of course, when we isolate the page, the page might be mapped but when we
try to migrate the page, the page would be not mapped. So it could be
migrated. But race is rare and although it happens, it's no big deal.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In async mode, compaction doesn't migrate dirty or writeback pages. So,
it's meaningless to pick the page and re-add it to lru list.
Of course, when we isolate the page in compaction, the page might be dirty
or writeback but when we try to migrate the page, the page would be not
dirty, writeback. So it could be migrated. But it's very unlikely as
isolate and migration cycle is much faster than writeout.
So, this patch helps cpu overhead and prevent unnecessary LRU churning.
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tejun Heo
