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| author | Nick Piggin <nickpiggin@yahoo.com.au> | 2006-03-25 03:07:09 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-25 08:22:53 -0800 |
| commit | c32ccd87bfd1414b0aabfcd8dbc7539ad23bcbaa (patch) | |
| tree | 612dc637976cbe36e8b72924a1f7bd76e75463fd /include/linux/inotify.h | |
| parent | bf36b9011e3c5b2739f9da2f6de8a6fa3edded32 (diff) | |
| download | lwn-c32ccd87bfd1414b0aabfcd8dbc7539ad23bcbaa.tar.gz lwn-c32ccd87bfd1414b0aabfcd8dbc7539ad23bcbaa.zip | |
[PATCH] inotify: lock avoidance with parent watch status in dentry
Previous inotify work avoidance is good when inotify is completely unused,
but it breaks down if even a single watch is in place anywhere in the
system. Robin Holt notices that udev is one such culprit - it slows down a
512-thread application on a 512 CPU system from 6 seconds to 22 minutes.
Solve this by adding a flag in the dentry that tells inotify whether or not
its parent inode has a watch on it. Event queueing to parent will skip
taking locks if this flag is cleared. Setting and clearing of this flag on
all child dentries versus event delivery: this is no in terms of race
cases, and that was shown to be equivalent to always performing the check.
The essential behaviour is that activity occuring _after_ a watch has been
added and _before_ it has been removed, will generate events.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Robert Love <rml@novell.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/inotify.h')
| -rw-r--r-- | include/linux/inotify.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/inotify.h b/include/linux/inotify.h index 267c88b5f742..09e00433c78e 100644 --- a/include/linux/inotify.h +++ b/include/linux/inotify.h @@ -71,6 +71,8 @@ struct inotify_event { #ifdef CONFIG_INOTIFY +extern void inotify_d_instantiate(struct dentry *, struct inode *); +extern void inotify_d_move(struct dentry *); extern void inotify_inode_queue_event(struct inode *, __u32, __u32, const char *); extern void inotify_dentry_parent_queue_event(struct dentry *, __u32, __u32, @@ -81,6 +83,15 @@ extern u32 inotify_get_cookie(void); #else +static inline void inotify_d_instantiate(struct dentry *dentry, + struct inode *inode) +{ +} + +static inline void inotify_d_move(struct dentry *dentry) +{ +} + static inline void inotify_inode_queue_event(struct inode *inode, __u32 mask, __u32 cookie, const char *filename) |