From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754515AbZEQPmA (ORCPT ); Sun, 17 May 2009 11:42:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753559AbZEQPlt (ORCPT ); Sun, 17 May 2009 11:41:49 -0400 Received: from mx2.redhat.com ([66.187.237.31]:42885 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753367AbZEQPls (ORCPT ); Sun, 17 May 2009 11:41:48 -0400 Subject: Re: [PATCH mmotm] fsnotify: don't slow everything down From: Eric Paris To: Hugh Dickins Cc: Andrew Morton , Al Viro , Christoph Hellwig , linux-kernel@vger.kernel.org In-Reply-To: References: Content-Type: text/plain Date: Sun, 17 May 2009 11:38:17 -0400 Message-Id: <1242574698.5212.35.camel@dhcp231-142.rdu.redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2009-05-17 at 14:52 +0100, Hugh Dickins wrote: > Two little fixes to mmotm's fsnotify-parent-event-notification.patch: > > Why is copying or building a kernel tree using twice as much system time > as before? Lots of time spent in __fsnotify_update_child_dentry_flags() > when it shouldn't even get called. Fix | to & in __fsnotify_parent(). I can't believe I didn't find that one in my testing, obviously it doesn't hurt anything but performance. > And it's probably a bad idea to have DCACHE_FSNOTIFY_PARENT_WATCHED > sharing the same d_flags bit as DCACHE_COOKIE: though the COOKIE bit has > prior claim, change it to keep the NOTIFY_PARENT_WATCHED bits together. If people feel strongly I can come up with a system to reuse the inotify flag now.... I planned on dropping the old inotify flag in a couple releases when I finally evict inotify entirely, it would be a performance hit, but I have a feeling a minimal one. In any case, when I push these patches along I'll probably move the new flag rather than _COOKIE since long term they won't be 'together' Acked-by: Eric Paris > Signed-off-by: Hugh Dickins > --- > > fs/notify/fsnotify.c | 2 +- > include/linux/dcache.h | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > --- mmotm/fs/notify/fsnotify.c 2009-05-14 11:27:38.000000000 +0100 > +++ linux/fs/notify/fsnotify.c 2009-05-17 13:31:23.000000000 +0100 > @@ -84,7 +84,7 @@ void __fsnotify_parent(struct dentry *de > bool send = false; > bool should_update_children = false; > > - if (!(dentry->d_flags | DCACHE_FSNOTIFY_PARENT_WATCHED)) > + if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) > return; > > spin_lock(&dentry->d_lock); > --- mmotm/include/linux/dcache.h 2009-05-14 11:27:39.000000000 +0100 > +++ linux/include/linux/dcache.h 2009-05-17 13:31:23.000000000 +0100 > @@ -183,7 +183,7 @@ d_iput: no no no yes > #define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched by inotify */ > #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0040 /* Parent inode is watched by some fsnotify listener */ > > -#define DCACHE_COOKIE 0x0040 /* For use by dcookie subsystem */ > +#define DCACHE_COOKIE 0x0080 /* For use by dcookie subsystem */ > > extern spinlock_t dcache_lock; > extern seqlock_t rename_lock;