From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763224AbZD3OHr (ORCPT ); Thu, 30 Apr 2009 10:07:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763233AbZD3OH0 (ORCPT ); Thu, 30 Apr 2009 10:07:26 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:47290 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763498AbZD3OHZ (ORCPT ); Thu, 30 Apr 2009 10:07:25 -0400 Date: Thu, 30 Apr 2009 16:06:42 +0200 From: Ingo Molnar To: Wu Fengguang Cc: Eric Paris , Andrew Morton , LKML , "linux-mm@kvack.org" , Matt Mackall , Christoph Lameter , Al Viro Subject: Re: [PATCH] use GFP_NOFS in kernel_event() Message-ID: <20090430140642.GB14696@elte.hu> References: <20090430020004.GA1898@localhost> <20090429191044.b6fceae2.akpm@linux-foundation.org> <1241097573.6020.7.camel@localhost.localdomain> <20090430134821.GB8644@localhost> <20090430140324.GA12033@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090430140324.GA12033@localhost> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Wu Fengguang wrote: > On Thu, Apr 30, 2009 at 09:48:21PM +0800, Wu Fengguang wrote: > > On Thu, Apr 30, 2009 at 09:19:33PM +0800, Eric Paris wrote: > > > inotify: lockdep annotation when watch being removed > > > > > > From: Eric Paris > > > > > > When a dentry is being evicted from memory pressure, if the inode associated > > > with that dentry has i_nlink == 0 we are going to drop all of the watches and > > > kick everything out. Lockdep complains that previously holding inotify_mutex > > > we did a __GFP_FS allocation and now __GFP_FS reclaim is taking that lock. > > > There is no deadlock or danger, since we know on this code path we are > > > actually cleaning up and evicting everything. So we move the lock into a new > > > class for clean up. > > > > I can reproduce the bug and hence confirm that this patch works, so > > > > Tested-by: Wu Fengguang > > btw, I really see no point to have one GFP_KERNEL and one GFP_NOFS > sitting side by side inside kernel_event(). So this patch? > > --- > inotify: use consistent GFP_KERNEL in kernel_event() > > kernel_event() has side by side kmem_cache_alloc(GFP_NOFS) > and kmalloc(GFP_KERNEL). Change to consistent GFP_KERNELs. > > cc: Al Viro > Signed-off-by: Wu Fengguang > --- > fs/notify/inotify/inotify_user.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- mm.orig/fs/notify/inotify/inotify_user.c > +++ mm/fs/notify/inotify/inotify_user.c > @@ -189,7 +189,7 @@ static struct inotify_kernel_event * ker > { > struct inotify_kernel_event *kevent; > > - kevent = kmem_cache_alloc(event_cachep, GFP_NOFS); > + kevent = kmem_cache_alloc(event_cachep, GFP_KERNEL); good point - this essentially reverts the earlier workaround. Ingo From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id BC1456B003D for ; Thu, 30 Apr 2009 10:06:53 -0400 (EDT) Date: Thu, 30 Apr 2009 16:06:42 +0200 From: Ingo Molnar Subject: Re: [PATCH] use GFP_NOFS in kernel_event() Message-ID: <20090430140642.GB14696@elte.hu> References: <20090430020004.GA1898@localhost> <20090429191044.b6fceae2.akpm@linux-foundation.org> <1241097573.6020.7.camel@localhost.localdomain> <20090430134821.GB8644@localhost> <20090430140324.GA12033@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090430140324.GA12033@localhost> Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Eric Paris , Andrew Morton , LKML , "linux-mm@kvack.org" , Matt Mackall , Christoph Lameter , Al Viro List-ID: * Wu Fengguang wrote: > On Thu, Apr 30, 2009 at 09:48:21PM +0800, Wu Fengguang wrote: > > On Thu, Apr 30, 2009 at 09:19:33PM +0800, Eric Paris wrote: > > > inotify: lockdep annotation when watch being removed > > > > > > From: Eric Paris > > > > > > When a dentry is being evicted from memory pressure, if the inode associated > > > with that dentry has i_nlink == 0 we are going to drop all of the watches and > > > kick everything out. Lockdep complains that previously holding inotify_mutex > > > we did a __GFP_FS allocation and now __GFP_FS reclaim is taking that lock. > > > There is no deadlock or danger, since we know on this code path we are > > > actually cleaning up and evicting everything. So we move the lock into a new > > > class for clean up. > > > > I can reproduce the bug and hence confirm that this patch works, so > > > > Tested-by: Wu Fengguang > > btw, I really see no point to have one GFP_KERNEL and one GFP_NOFS > sitting side by side inside kernel_event(). So this patch? > > --- > inotify: use consistent GFP_KERNEL in kernel_event() > > kernel_event() has side by side kmem_cache_alloc(GFP_NOFS) > and kmalloc(GFP_KERNEL). Change to consistent GFP_KERNELs. > > cc: Al Viro > Signed-off-by: Wu Fengguang > --- > fs/notify/inotify/inotify_user.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- mm.orig/fs/notify/inotify/inotify_user.c > +++ mm/fs/notify/inotify/inotify_user.c > @@ -189,7 +189,7 @@ static struct inotify_kernel_event * ker > { > struct inotify_kernel_event *kevent; > > - kevent = kmem_cache_alloc(event_cachep, GFP_NOFS); > + kevent = kmem_cache_alloc(event_cachep, GFP_KERNEL); good point - this essentially reverts the earlier workaround. Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org