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authorEric Paris <eparis@redhat.com>2009-07-15 15:49:52 -0400
committerEric Paris <eparis@redhat.com>2009-07-21 15:26:27 -0400
commitf44aebcc566d1d6275f7191867b9633dc11de2ee (patch)
treea5faaf5ca8e1360f359ee22ad29582992596c3e6 /fs/notify/inotify/inotify_user.c
parentc05594b62125c528d93af3a78229793aae36df7f (diff)
inotify: use GFP_NOFS under potential memory pressure
inotify can have a watchs removed under filesystem reclaim. ================================= [ INFO: inconsistent lock state ] 2.6.31-rc2 #16 --------------------------------- inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage. khubd/217 [HC0[0]:SC0[0]:HE1:SE1] takes: (iprune_mutex){+.+.?.}, at: [<c10ba899>] invalidate_inodes+0x20/0xe3 {IN-RECLAIM_FS-W} state was registered at: [<c10536ab>] __lock_acquire+0x2c9/0xac4 [<c1053f45>] lock_acquire+0x9f/0xc2 [<c1308872>] __mutex_lock_common+0x2d/0x323 [<c1308c00>] mutex_lock_nested+0x2e/0x36 [<c10ba6ff>] shrink_icache_memory+0x38/0x1b2 [<c108bfb6>] shrink_slab+0xe2/0x13c [<c108c3e1>] kswapd+0x3d1/0x55d [<c10449b5>] kthread+0x66/0x6b [<c1003fdf>] kernel_thread_helper+0x7/0x10 [<ffffffff>] 0xffffffff Two things are needed to fix this. First we need a method to tell fsnotify_create_event() to use GFP_NOFS and second we need to stop using one global IN_IGNORED event and allocate them one at a time. This solves current issues with multiple IN_IGNORED on a queue having tail drop problems and simplifies the allocations since we don't have to worry about two tasks opperating on the IGNORED event concurrently. Signed-off-by: Eric Paris <eparis@redhat.com>
Diffstat (limited to 'fs/notify/inotify/inotify_user.c')
-rw-r--r--fs/notify/inotify/inotify_user.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index 726118a5845b..f30d9bbc2e1b 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -57,7 +57,6 @@ int inotify_max_user_watches __read_mostly;
57 57
58static struct kmem_cache *inotify_inode_mark_cachep __read_mostly; 58static struct kmem_cache *inotify_inode_mark_cachep __read_mostly;
59struct kmem_cache *event_priv_cachep __read_mostly; 59struct kmem_cache *event_priv_cachep __read_mostly;
60static struct fsnotify_event *inotify_ignored_event;
61 60
62/* 61/*
63 * When inotify registers a new group it increments this and uses that 62 * When inotify registers a new group it increments this and uses that
@@ -384,12 +383,19 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
384 struct fsnotify_group *group) 383 struct fsnotify_group *group)
385{ 384{
386 struct inotify_inode_mark_entry *ientry; 385 struct inotify_inode_mark_entry *ientry;
386 struct fsnotify_event *ignored_event;
387 struct inotify_event_private_data *event_priv; 387 struct inotify_event_private_data *event_priv;
388 struct fsnotify_event_private_data *fsn_event_priv; 388 struct fsnotify_event_private_data *fsn_event_priv;
389 389
390 ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL,
391 FSNOTIFY_EVENT_NONE, NULL, 0,
392 GFP_NOFS);
393 if (!ignored_event)
394 return;
395
390 ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); 396 ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
391 397
392 event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL); 398 event_priv = kmem_cache_alloc(event_priv_cachep, GFP_NOFS);
393 if (unlikely(!event_priv)) 399 if (unlikely(!event_priv))
394 goto skip_send_ignore; 400 goto skip_send_ignore;
395 401
@@ -398,7 +404,7 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
398 fsn_event_priv->group = group; 404 fsn_event_priv->group = group;
399 event_priv->wd = ientry->wd; 405 event_priv->wd = ientry->wd;
400 406
401 fsnotify_add_notify_event(group, inotify_ignored_event, fsn_event_priv); 407 fsnotify_add_notify_event(group, ignored_event, fsn_event_priv);
402 408
403 /* did the private data get added? */ 409 /* did the private data get added? */
404 if (list_empty(&fsn_event_priv->event_list)) 410 if (list_empty(&fsn_event_priv->event_list))
@@ -406,6 +412,9 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
406 412
407skip_send_ignore: 413skip_send_ignore:
408 414
415 /* matches the reference taken when the event was created */
416 fsnotify_put_event(ignored_event);
417
409 /* remove this entry from the idr */ 418 /* remove this entry from the idr */
410 inotify_remove_from_idr(group, ientry); 419 inotify_remove_from_idr(group, ientry);
411 420
@@ -748,9 +757,6 @@ static int __init inotify_user_setup(void)
748 757
749 inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC); 758 inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC);
750 event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC); 759 event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC);
751 inotify_ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, FSNOTIFY_EVENT_NONE, NULL, 0);
752 if (!inotify_ignored_event)
753 panic("unable to allocate the inotify ignored event\n");
754 760
755 inotify_max_queued_events = 16384; 761 inotify_max_queued_events = 16384;
756 inotify_max_user_instances = 128; 762 inotify_max_user_instances = 128;