fee096deb4
Catch an overly long wait for an old, dying active object when we want to
replace it with a new one. The probability is that all the slow-work threads
are hogged, and the delete can't get a look in.
What we do instead is:
(1) if there's nothing in the slow work queue, we sleep until either the dying
object has finished dying or there is something in the slow work queue
behind which we can queue our object.
(2) if there is something in the slow work queue, we return ETIMEDOUT to
fscache_lookup_object(), which then puts us back on the slow work queue,
presumably behind the deletion that we're blocked by. We are then
deferred for a while until we work our way back through the queue -
without blocking a slow-work thread unnecessarily.
A backtrace similar to the following may appear in the log without this patch:
INFO: task kslowd004:5711 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kslowd004 D 0000000000000000 0 5711 2 0x00000080
ffff88000340bb80 0000000000000046 ffff88002550d000 0000000000000000
ffff88002550d000 0000000000000007 ffff88000340bfd8 ffff88002550d2a8
000000000000ddf0 00000000000118c0 00000000000118c0 ffff88002550d2a8
Call Trace:
[<ffffffff81058e21>] ? trace_hardirqs_on+0xd/0xf
[<ffffffffa011c4d8>] ? cachefiles_wait_bit+0x0/0xd [cachefiles]
[<ffffffffa011c4e1>] cachefiles_wait_bit+0x9/0xd [cachefiles]
[<ffffffff81353153>] __wait_on_bit+0x43/0x76
[<ffffffff8111ae39>] ? ext3_xattr_get+0x1ec/0x270
[<ffffffff813531ef>] out_of_line_wait_on_bit+0x69/0x74
[<ffffffffa011c4d8>] ? cachefiles_wait_bit+0x0/0xd [cachefiles]
[<ffffffff8104c125>] ? wake_bit_function+0x0/0x2e
[<ffffffffa011bc79>] cachefiles_mark_object_active+0x203/0x23b [cachefiles]
[<ffffffffa011c209>] cachefiles_walk_to_object+0x558/0x827 [cachefiles]
[<ffffffffa011a429>] cachefiles_lookup_object+0xac/0x12a [cachefiles]
[<ffffffffa00aa1e9>] fscache_lookup_object+0x1c7/0x214 [fscache]
[<ffffffffa00aafc5>] fscache_object_state_machine+0xa5/0x52d [fscache]
[<ffffffffa00ab4ac>] fscache_object_slow_work_execute+0x5f/0xa0 [fscache]
[<ffffffff81082093>] slow_work_execute+0x18f/0x2d1
[<ffffffff8108239a>] slow_work_thread+0x1c5/0x308
[<ffffffff8104c0f1>] ? autoremove_wake_function+0x0/0x34
[<ffffffff810821d5>] ? slow_work_thread+0x0/0x308
[<ffffffff8104be91>] kthread+0x7a/0x82
[<ffffffff8100beda>] child_rip+0xa/0x20
[<ffffffff8100b87c>] ? restore_args+0x0/0x30
[<ffffffff8104be17>] ? kthread+0x0/0x82
[<ffffffff8100bed0>] ? child_rip+0x0/0x20
1 lock held by kslowd004/5711:
#0: (&sb->s_type->i_mutex_key#7/1){+.+.+.}, at: [<ffffffffa011be64>] cachefiles_walk_to_object+0x1b3/0x827 [cachefiles]
Signed-off-by: David Howells <dhowells@redhat.com>
280 lines
9.6 KiB
C
280 lines
9.6 KiB
C
/* FS-Cache statistics
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define FSCACHE_DEBUG_LEVEL THREAD
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include "internal.h"
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/*
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* operation counters
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*/
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atomic_t fscache_n_op_pend;
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atomic_t fscache_n_op_run;
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atomic_t fscache_n_op_enqueue;
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atomic_t fscache_n_op_requeue;
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atomic_t fscache_n_op_deferred_release;
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atomic_t fscache_n_op_release;
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atomic_t fscache_n_op_gc;
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atomic_t fscache_n_op_cancelled;
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atomic_t fscache_n_op_rejected;
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atomic_t fscache_n_attr_changed;
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atomic_t fscache_n_attr_changed_ok;
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atomic_t fscache_n_attr_changed_nobufs;
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atomic_t fscache_n_attr_changed_nomem;
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atomic_t fscache_n_attr_changed_calls;
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atomic_t fscache_n_allocs;
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atomic_t fscache_n_allocs_ok;
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atomic_t fscache_n_allocs_wait;
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atomic_t fscache_n_allocs_nobufs;
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atomic_t fscache_n_allocs_intr;
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atomic_t fscache_n_allocs_object_dead;
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atomic_t fscache_n_alloc_ops;
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atomic_t fscache_n_alloc_op_waits;
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atomic_t fscache_n_retrievals;
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atomic_t fscache_n_retrievals_ok;
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atomic_t fscache_n_retrievals_wait;
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atomic_t fscache_n_retrievals_nodata;
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atomic_t fscache_n_retrievals_nobufs;
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atomic_t fscache_n_retrievals_intr;
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atomic_t fscache_n_retrievals_nomem;
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atomic_t fscache_n_retrievals_object_dead;
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atomic_t fscache_n_retrieval_ops;
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atomic_t fscache_n_retrieval_op_waits;
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atomic_t fscache_n_stores;
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atomic_t fscache_n_stores_ok;
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atomic_t fscache_n_stores_again;
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atomic_t fscache_n_stores_nobufs;
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atomic_t fscache_n_stores_oom;
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atomic_t fscache_n_store_ops;
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atomic_t fscache_n_store_calls;
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atomic_t fscache_n_store_pages;
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atomic_t fscache_n_store_radix_deletes;
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atomic_t fscache_n_store_pages_over_limit;
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atomic_t fscache_n_store_vmscan_not_storing;
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atomic_t fscache_n_store_vmscan_gone;
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atomic_t fscache_n_store_vmscan_busy;
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atomic_t fscache_n_store_vmscan_cancelled;
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atomic_t fscache_n_marks;
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atomic_t fscache_n_uncaches;
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atomic_t fscache_n_acquires;
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atomic_t fscache_n_acquires_null;
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atomic_t fscache_n_acquires_no_cache;
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atomic_t fscache_n_acquires_ok;
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atomic_t fscache_n_acquires_nobufs;
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atomic_t fscache_n_acquires_oom;
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atomic_t fscache_n_updates;
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atomic_t fscache_n_updates_null;
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atomic_t fscache_n_updates_run;
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atomic_t fscache_n_relinquishes;
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atomic_t fscache_n_relinquishes_null;
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atomic_t fscache_n_relinquishes_waitcrt;
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atomic_t fscache_n_relinquishes_retire;
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atomic_t fscache_n_cookie_index;
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atomic_t fscache_n_cookie_data;
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atomic_t fscache_n_cookie_special;
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atomic_t fscache_n_object_alloc;
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atomic_t fscache_n_object_no_alloc;
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atomic_t fscache_n_object_lookups;
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atomic_t fscache_n_object_lookups_negative;
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atomic_t fscache_n_object_lookups_positive;
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atomic_t fscache_n_object_lookups_timed_out;
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atomic_t fscache_n_object_created;
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atomic_t fscache_n_object_avail;
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atomic_t fscache_n_object_dead;
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atomic_t fscache_n_checkaux_none;
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atomic_t fscache_n_checkaux_okay;
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atomic_t fscache_n_checkaux_update;
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atomic_t fscache_n_checkaux_obsolete;
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atomic_t fscache_n_cop_alloc_object;
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atomic_t fscache_n_cop_lookup_object;
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atomic_t fscache_n_cop_lookup_complete;
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atomic_t fscache_n_cop_grab_object;
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atomic_t fscache_n_cop_update_object;
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atomic_t fscache_n_cop_drop_object;
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atomic_t fscache_n_cop_put_object;
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atomic_t fscache_n_cop_sync_cache;
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atomic_t fscache_n_cop_attr_changed;
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atomic_t fscache_n_cop_read_or_alloc_page;
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atomic_t fscache_n_cop_read_or_alloc_pages;
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atomic_t fscache_n_cop_allocate_page;
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atomic_t fscache_n_cop_allocate_pages;
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atomic_t fscache_n_cop_write_page;
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atomic_t fscache_n_cop_uncache_page;
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atomic_t fscache_n_cop_dissociate_pages;
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/*
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* display the general statistics
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*/
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static int fscache_stats_show(struct seq_file *m, void *v)
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{
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seq_puts(m, "FS-Cache statistics\n");
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seq_printf(m, "Cookies: idx=%u dat=%u spc=%u\n",
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atomic_read(&fscache_n_cookie_index),
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atomic_read(&fscache_n_cookie_data),
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atomic_read(&fscache_n_cookie_special));
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seq_printf(m, "Objects: alc=%u nal=%u avl=%u ded=%u\n",
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atomic_read(&fscache_n_object_alloc),
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atomic_read(&fscache_n_object_no_alloc),
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atomic_read(&fscache_n_object_avail),
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atomic_read(&fscache_n_object_dead));
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seq_printf(m, "ChkAux : non=%u ok=%u upd=%u obs=%u\n",
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atomic_read(&fscache_n_checkaux_none),
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atomic_read(&fscache_n_checkaux_okay),
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atomic_read(&fscache_n_checkaux_update),
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atomic_read(&fscache_n_checkaux_obsolete));
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seq_printf(m, "Pages : mrk=%u unc=%u\n",
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atomic_read(&fscache_n_marks),
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atomic_read(&fscache_n_uncaches));
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seq_printf(m, "Acquire: n=%u nul=%u noc=%u ok=%u nbf=%u"
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" oom=%u\n",
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atomic_read(&fscache_n_acquires),
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atomic_read(&fscache_n_acquires_null),
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atomic_read(&fscache_n_acquires_no_cache),
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atomic_read(&fscache_n_acquires_ok),
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atomic_read(&fscache_n_acquires_nobufs),
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atomic_read(&fscache_n_acquires_oom));
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seq_printf(m, "Lookups: n=%u neg=%u pos=%u crt=%u tmo=%u\n",
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atomic_read(&fscache_n_object_lookups),
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atomic_read(&fscache_n_object_lookups_negative),
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atomic_read(&fscache_n_object_lookups_positive),
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atomic_read(&fscache_n_object_lookups_timed_out),
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atomic_read(&fscache_n_object_created));
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seq_printf(m, "Updates: n=%u nul=%u run=%u\n",
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atomic_read(&fscache_n_updates),
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atomic_read(&fscache_n_updates_null),
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atomic_read(&fscache_n_updates_run));
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seq_printf(m, "Relinqs: n=%u nul=%u wcr=%u rtr=%u\n",
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atomic_read(&fscache_n_relinquishes),
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atomic_read(&fscache_n_relinquishes_null),
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atomic_read(&fscache_n_relinquishes_waitcrt),
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atomic_read(&fscache_n_relinquishes_retire));
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seq_printf(m, "AttrChg: n=%u ok=%u nbf=%u oom=%u run=%u\n",
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atomic_read(&fscache_n_attr_changed),
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atomic_read(&fscache_n_attr_changed_ok),
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atomic_read(&fscache_n_attr_changed_nobufs),
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atomic_read(&fscache_n_attr_changed_nomem),
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atomic_read(&fscache_n_attr_changed_calls));
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seq_printf(m, "Allocs : n=%u ok=%u wt=%u nbf=%u int=%u\n",
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atomic_read(&fscache_n_allocs),
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atomic_read(&fscache_n_allocs_ok),
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atomic_read(&fscache_n_allocs_wait),
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atomic_read(&fscache_n_allocs_nobufs),
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atomic_read(&fscache_n_allocs_intr));
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seq_printf(m, "Allocs : ops=%u owt=%u abt=%u\n",
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atomic_read(&fscache_n_alloc_ops),
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atomic_read(&fscache_n_alloc_op_waits),
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atomic_read(&fscache_n_allocs_object_dead));
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seq_printf(m, "Retrvls: n=%u ok=%u wt=%u nod=%u nbf=%u"
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" int=%u oom=%u\n",
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atomic_read(&fscache_n_retrievals),
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atomic_read(&fscache_n_retrievals_ok),
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atomic_read(&fscache_n_retrievals_wait),
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atomic_read(&fscache_n_retrievals_nodata),
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atomic_read(&fscache_n_retrievals_nobufs),
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atomic_read(&fscache_n_retrievals_intr),
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atomic_read(&fscache_n_retrievals_nomem));
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seq_printf(m, "Retrvls: ops=%u owt=%u abt=%u\n",
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atomic_read(&fscache_n_retrieval_ops),
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atomic_read(&fscache_n_retrieval_op_waits),
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atomic_read(&fscache_n_retrievals_object_dead));
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seq_printf(m, "Stores : n=%u ok=%u agn=%u nbf=%u oom=%u\n",
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atomic_read(&fscache_n_stores),
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atomic_read(&fscache_n_stores_ok),
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atomic_read(&fscache_n_stores_again),
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atomic_read(&fscache_n_stores_nobufs),
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atomic_read(&fscache_n_stores_oom));
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seq_printf(m, "Stores : ops=%u run=%u pgs=%u rxd=%u olm=%u\n",
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atomic_read(&fscache_n_store_ops),
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atomic_read(&fscache_n_store_calls),
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atomic_read(&fscache_n_store_pages),
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atomic_read(&fscache_n_store_radix_deletes),
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atomic_read(&fscache_n_store_pages_over_limit));
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seq_printf(m, "VmScan : nos=%u gon=%u bsy=%u can=%u\n",
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atomic_read(&fscache_n_store_vmscan_not_storing),
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atomic_read(&fscache_n_store_vmscan_gone),
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atomic_read(&fscache_n_store_vmscan_busy),
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atomic_read(&fscache_n_store_vmscan_cancelled));
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seq_printf(m, "Ops : pend=%u run=%u enq=%u can=%u rej=%u\n",
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atomic_read(&fscache_n_op_pend),
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atomic_read(&fscache_n_op_run),
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atomic_read(&fscache_n_op_enqueue),
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atomic_read(&fscache_n_op_cancelled),
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atomic_read(&fscache_n_op_rejected));
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seq_printf(m, "Ops : dfr=%u rel=%u gc=%u\n",
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atomic_read(&fscache_n_op_deferred_release),
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atomic_read(&fscache_n_op_release),
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atomic_read(&fscache_n_op_gc));
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seq_printf(m, "CacheOp: alo=%d luo=%d luc=%d gro=%d\n",
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atomic_read(&fscache_n_cop_alloc_object),
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atomic_read(&fscache_n_cop_lookup_object),
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atomic_read(&fscache_n_cop_lookup_complete),
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atomic_read(&fscache_n_cop_grab_object));
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seq_printf(m, "CacheOp: upo=%d dro=%d pto=%d atc=%d syn=%d\n",
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atomic_read(&fscache_n_cop_update_object),
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atomic_read(&fscache_n_cop_drop_object),
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atomic_read(&fscache_n_cop_put_object),
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atomic_read(&fscache_n_cop_attr_changed),
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atomic_read(&fscache_n_cop_sync_cache));
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seq_printf(m, "CacheOp: rap=%d ras=%d alp=%d als=%d wrp=%d ucp=%d dsp=%d\n",
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atomic_read(&fscache_n_cop_read_or_alloc_page),
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atomic_read(&fscache_n_cop_read_or_alloc_pages),
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atomic_read(&fscache_n_cop_allocate_page),
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atomic_read(&fscache_n_cop_allocate_pages),
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atomic_read(&fscache_n_cop_write_page),
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atomic_read(&fscache_n_cop_uncache_page),
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atomic_read(&fscache_n_cop_dissociate_pages));
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return 0;
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}
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/*
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* open "/proc/fs/fscache/stats" allowing provision of a statistical summary
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*/
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static int fscache_stats_open(struct inode *inode, struct file *file)
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{
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return single_open(file, fscache_stats_show, NULL);
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}
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const struct file_operations fscache_stats_fops = {
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.owner = THIS_MODULE,
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.open = fscache_stats_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release,
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};
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