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| author | Nick Piggin <nickpiggin@yahoo.com.au> | 2006-03-25 12:07:09 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-25 17:22:53 +0100 |
| commit | c32ccd87bfd1414b0aabfcd8dbc7539ad23bcbaa (patch) | |
| tree | 612dc637976cbe36e8b72924a1f7bd76e75463fd /fs/dcache.c | |
| parent | [PATCH] sysrq cleanup (diff) | |
| download | linux-c32ccd87bfd1414b0aabfcd8dbc7539ad23bcbaa.tar.xz linux-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 'fs/dcache.c')
| -rw-r--r-- | fs/dcache.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 139e5fd22fa6..0f7ec12d65ff 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -802,6 +802,7 @@ void d_instantiate(struct dentry *entry, struct inode * inode) if (inode) list_add(&entry->d_alias, &inode->i_dentry); entry->d_inode = inode; + fsnotify_d_instantiate(entry, inode); spin_unlock(&dcache_lock); security_d_instantiate(entry, inode); } @@ -853,6 +854,7 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) list_add(&entry->d_alias, &inode->i_dentry); do_negative: entry->d_inode = inode; + fsnotify_d_instantiate(entry, inode); spin_unlock(&dcache_lock); security_d_instantiate(entry, inode); return NULL; @@ -983,6 +985,7 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) new = __d_find_alias(inode, 1); if (new) { BUG_ON(!(new->d_flags & DCACHE_DISCONNECTED)); + fsnotify_d_instantiate(new, inode); spin_unlock(&dcache_lock); security_d_instantiate(new, inode); d_rehash(dentry); @@ -992,6 +995,7 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) /* d_instantiate takes dcache_lock, so we do it by hand */ list_add(&dentry->d_alias, &inode->i_dentry); dentry->d_inode = inode; + fsnotify_d_instantiate(dentry, inode); spin_unlock(&dcache_lock); security_d_instantiate(dentry, inode); d_rehash(dentry); @@ -1176,6 +1180,9 @@ void d_delete(struct dentry * dentry) spin_lock(&dentry->d_lock); isdir = S_ISDIR(dentry->d_inode->i_mode); if (atomic_read(&dentry->d_count) == 1) { + /* remove this and other inotify debug checks after 2.6.18 */ + dentry->d_flags &= ~DCACHE_INOTIFY_PARENT_WATCHED; + dentry_iput(dentry); fsnotify_nameremove(dentry, isdir); return; @@ -1342,6 +1349,7 @@ already_unhashed: list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs); spin_unlock(&target->d_lock); + fsnotify_d_move(dentry); spin_unlock(&dentry->d_lock); write_sequnlock(&rename_lock); spin_unlock(&dcache_lock); |