From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757607Ab1DMBXd (ORCPT ); Tue, 12 Apr 2011 21:23:33 -0400 Received: from mail-pw0-f46.google.com ([209.85.160.46]:33291 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757447Ab1DMBXb (ORCPT ); Tue, 12 Apr 2011 21:23:31 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=Ej2G9zkNTIuZ4U/9Zv21n+rQ08zafhQEVdG5loy7T8q0VRhv1QXJe42GS+aENx4/ZJ ot1mpucuHcNSsz3gvaS92/vPWeFQrVtNxhHuLYRIYvlCp8na8B+20A8FD4aWyUBSrIGE VDvTdrZ1C961BxsGOxem/tmW+5iKE+jmPxuPo= MIME-Version: 1.0 In-Reply-To: <20110412154906.70829d60.akpm@linux-foundation.org> References: <20110315132527.130FB80018F1@mail1005.cent> <20110317001519.GB18911@kroah.com> <20110407120112.E08DCA03@pobox.sk> <4D9D8FAA.9080405@suse.cz> <1302177428.3357.25.camel@edumazet-laptop> <1302178426.3357.34.camel@edumazet-laptop> <1302190586.3357.45.camel@edumazet-laptop> <20110412154906.70829d60.akpm@linux-foundation.org> From: Changli Gao Date: Wed, 13 Apr 2011 09:23:11 +0800 Message-ID: Subject: Re: Regression from 2.6.36 To: Andrew Morton Cc: Eric Dumazet , =?ISO-8859-1?Q?Am=E9rico_Wang?= , Jiri Slaby , azurIt , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Jiri Slaby Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 13, 2011 at 6:49 AM, Andrew Morton wrote: > > It's somewhat unclear (to me) what caused this regression. > > Is it because the kernel is now doing large kmalloc()s for the fdtable, > and this makes the page allocator go nuts trying to satisfy high-order > page allocation requests? > > Is it because the kernel now will usually free the fdtable > synchronously within the rcu callback, rather than deferring this to a > workqueue? > > The latter seems unlikely, so I'm thinking this was a case of > high-order-allocations-considered-harmful? > Maybe, but I am not sure. Maybe my patch causes too many inner fragments. For example, when asking for 5 pages, get 8 pages, and 3 pages are wasted, then memory thrash happens finally. -- Regards, Changli Gao(xiaosuo@gmail.com) From mboxrd@z Thu Jan 1 00:00:00 1970 From: Changli Gao Subject: Re: Regression from 2.6.36 Date: Wed, 13 Apr 2011 09:23:11 +0800 Message-ID: References: <20110315132527.130FB80018F1@mail1005.cent> <20110317001519.GB18911@kroah.com> <20110407120112.E08DCA03@pobox.sk> <4D9D8FAA.9080405@suse.cz> <1302177428.3357.25.camel@edumazet-laptop> <1302178426.3357.34.camel@edumazet-laptop> <1302190586.3357.45.camel@edumazet-laptop> <20110412154906.70829d60.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Eric Dumazet , =?ISO-8859-1?Q?Am=E9rico_Wang?= , Jiri Slaby , azurIt , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Jiri Slaby To: Andrew Morton Return-path: In-Reply-To: <20110412154906.70829d60.akpm@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Apr 13, 2011 at 6:49 AM, Andrew Morton wrote: > > It's somewhat unclear (to me) what caused this regression. > > Is it because the kernel is now doing large kmalloc()s for the fdtable, > and this makes the page allocator go nuts trying to satisfy high-order > page allocation requests? > > Is it because the kernel now will usually free the fdtable > synchronously within the rcu callback, rather than deferring this to a > workqueue? > > The latter seems unlikely, so I'm thinking this was a case of > high-order-allocations-considered-harmful? > Maybe, but I am not sure. Maybe my patch causes too many inner fragments. For example, when asking for 5 pages, get 8 pages, and 3 pages are wasted, then memory thrash happens finally. -- Regards, Changli Gao(xiaosuo@gmail.com) -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org