lkml.org 
[lkml]   [2020]   [Jul]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Date
    SubjectRe: [fsnotify] c738fbabb0: will-it-scale.per_process_ops -9.5% regression
    On Tue, Jul 21, 2020 at 3:15 AM kernel test robot <rong.a.chen@intel.com> wrote:
    >
    > Greeting,
    >
    > FYI, we noticed a -9.5% regression of will-it-scale.per_process_ops due to commit:
    >
    >
    > commit: c738fbabb0ff62d0f9a9572e56e65d05a1b34c6a ("fsnotify: fold fsnotify() call into fsnotify_parent()")

    Strange, that's a pretty dumb patch moving some inlined code from one
    function to
    another (assuming there are no fsnotify marks in this test).

    Unless I am missing something the only thing that changes slightly is
    an extra d_inode(file->f_path.dentry) deference.
    I can get rid of it.

    Is it possible to ask for a re-test with fix patch (attached)?

    Thanks,
    Amir.
    From 26dc3d2bff623768cbbd0c8053ddd6390fd828d2 Mon Sep 17 00:00:00 2001
    From: Amir Goldstein <amir73il@gmail.com>
    Date: Tue, 21 Jul 2020 18:52:18 +0300
    Subject: [PATCH] fsnotify: pass inode to fsnotify_parent()

    We can get inode by dereferenceing dentry->d_inode, but that may have
    performance impact in the fast path of non watched file.

    Kernel test robot reported a performance regression in concurrent open
    workload, so maybe that can fix it.

    Reported-by: kernel test robot <rong.a.chen@intel.com>
    Fixes: c738fbabb0ff ("fsnotify: fold fsnotify() call into fsnotify_parent()")
    Signed-off-by: Amir Goldstein <amir73il@gmail.com>
    ---
    include/linux/fsnotify.h | 11 ++++++-----
    1 file changed, 6 insertions(+), 5 deletions(-)

    diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
    index 316c9b820517..d49e5318aad9 100644
    --- a/include/linux/fsnotify.h
    +++ b/include/linux/fsnotify.h
    @@ -46,10 +46,9 @@ static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,

    /* Notify this dentry's parent about a child's events. */
    static inline int fsnotify_parent(struct dentry *dentry, __u32 mask,
    - const void *data, int data_type)
    + const void *data, int data_type,
    + struct inode *inode)
    {
    - struct inode *inode = d_inode(dentry);
    -
    if (S_ISDIR(inode->i_mode))
    mask |= FS_ISDIR;

    @@ -68,7 +67,8 @@ static inline int fsnotify_parent(struct dentry *dentry, __u32 mask,
    */
    static inline void fsnotify_dentry(struct dentry *dentry, __u32 mask)
    {
    - fsnotify_parent(dentry, mask, d_inode(dentry), FSNOTIFY_EVENT_INODE);
    + fsnotify_parent(dentry, mask, d_inode(dentry), FSNOTIFY_EVENT_INODE,
    + d_inode(dentry));
    }

    static inline int fsnotify_file(struct file *file, __u32 mask)
    @@ -78,7 +78,8 @@ static inline int fsnotify_file(struct file *file, __u32 mask)
    if (file->f_mode & FMODE_NONOTIFY)
    return 0;

    - return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
    + return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH,
    + file_inode(file));
    }

    /* Simple call site for access decisions */
    --
    2.17.1
    \
     
     \ /
      Last update: 2020-07-21 18:02    [W:3.468 / U:0.236 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site