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| author | Alexey Dobriyan <adobriyan@gmail.com> | 2014-08-08 14:21:27 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-08 15:57:22 -0700 |
| commit | 335eb53158466a4c4d018fa53ceb8c8ba1067fa3 (patch) | |
| tree | f12db91b65fa3ea85bad2610aab8dfa3d8f4dfc8 | |
| parent | dbcdb504417ae108a20454ef89776a614b948571 (diff) | |
| download | linux-335eb53158466a4c4d018fa53ceb8c8ba1067fa3.tar.gz linux-335eb53158466a4c4d018fa53ceb8c8ba1067fa3.tar.bz2 linux-335eb53158466a4c4d018fa53ceb8c8ba1067fa3.zip | |
proc: faster /proc/$PID lookup
Currently lookup for /proc/$PID first goes through spinlock and whole list
of misc /proc entries only to confirm that, yes, /proc/42 can not possibly
match random proc entry.
List is is several dozens entries long (52 entries on my setup).
None of this is necessary.
Try to convert dentry name to integer first.
If it works, it must be /proc/$PID.
If it doesn't, it must be random proc entry.
Based on patch from Al Viro.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/proc/base.c | 2 | ||||
| -rw-r--r-- | fs/proc/root.c | 4 |
2 files changed, 3 insertions, 3 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 11375216b493..35afb2eb4a6f 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2780,7 +2780,7 @@ out: struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags) { - int result = 0; + int result = -ENOENT; struct task_struct *task; unsigned tgid; struct pid_namespace *ns; diff --git a/fs/proc/root.c b/fs/proc/root.c index 5dbadecb234d..574bafc41f0b 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -199,10 +199,10 @@ static int proc_root_getattr(struct vfsmount *mnt, struct dentry *dentry, struct static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags) { - if (!proc_lookup(dir, dentry, flags)) + if (!proc_pid_lookup(dir, dentry, flags)) return NULL; - return proc_pid_lookup(dir, dentry, flags); + return proc_lookup(dir, dentry, flags); } static int proc_root_readdir(struct file *file, struct dir_context *ctx) |