From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o4R4MYFD108749 for ; Wed, 26 May 2010 23:22:34 -0500 Received: from mx2.suse.de (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 94EBDA645A6 for ; Wed, 26 May 2010 21:26:45 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) by cuda.sgi.com with ESMTP id lFIfJkuSUG7GICdU for ; Wed, 26 May 2010 21:26:45 -0700 (PDT) Date: Thu, 27 May 2010 14:24:53 +1000 From: Nick Piggin Subject: Re: [PATCH 3/5] superblock: introduce per-sb cache shrinker infrastructure Message-ID: <20100527042453.GI22536@laptop> References: <1274777588-21494-1-git-send-email-david@fromorbit.com> <1274777588-21494-4-git-send-email-david@fromorbit.com> <20100526164116.GD22536@laptop> <20100526231214.GB1395@dastard> <20100527021905.GG22536@laptop> <20100527040704.GJ12087@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100527040704.GJ12087@dastard> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, xfs@oss.sgi.com On Thu, May 27, 2010 at 02:07:04PM +1000, Dave Chinner wrote: > On Thu, May 27, 2010 at 12:19:05PM +1000, Nick Piggin wrote: > > On Thu, May 27, 2010 at 09:12:14AM +1000, Dave Chinner wrote: > > > On Thu, May 27, 2010 at 02:41:16AM +1000, Nick Piggin wrote: > > > > > + count = ((sb->s_nr_dentry_unused + sb->s_nr_inodes_unused) / 100) > > > > > + * sysctl_vfs_cache_pressure; > > > > > > > > Do you think truncating in the divisions is at all a problem? It > > > > probably doesn't matter much I suppose. > > > > > > Same code as currently exists. IIRC, the reasoning is that if we've > > > got less that 100 objects to reclaim, then we're unlikely to be able > > > to free up any memory from the caches, anyway. > > > > Yeah, which is why I stop short of saying you should change it in > > this patch. > > > > But I think we should ensure things can get reclaimed eventually. > > 100 objects could be 100 slabs, which could be anything from > > half a meg to half a dozen. Multiplied by each of the caches. > > Could be significant in small systems. > > True, but usually there are busy objects in the dentry and inode > slabs, so it shouldn't be a significant issue. We can probably > address such problems if they can be demonstrated to be an issue in > a separate patch set.... I didn't want to say it is a problem with your patchset, I just thought of it when reviewing. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933334Ab0E0EY6 (ORCPT ); Thu, 27 May 2010 00:24:58 -0400 Received: from cantor2.suse.de ([195.135.220.15]:35057 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750724Ab0E0EY4 (ORCPT ); Thu, 27 May 2010 00:24:56 -0400 Date: Thu, 27 May 2010 14:24:53 +1000 From: Nick Piggin To: Dave Chinner Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, xfs@oss.sgi.com Subject: Re: [PATCH 3/5] superblock: introduce per-sb cache shrinker infrastructure Message-ID: <20100527042453.GI22536@laptop> References: <1274777588-21494-1-git-send-email-david@fromorbit.com> <1274777588-21494-4-git-send-email-david@fromorbit.com> <20100526164116.GD22536@laptop> <20100526231214.GB1395@dastard> <20100527021905.GG22536@laptop> <20100527040704.GJ12087@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100527040704.GJ12087@dastard> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 27, 2010 at 02:07:04PM +1000, Dave Chinner wrote: > On Thu, May 27, 2010 at 12:19:05PM +1000, Nick Piggin wrote: > > On Thu, May 27, 2010 at 09:12:14AM +1000, Dave Chinner wrote: > > > On Thu, May 27, 2010 at 02:41:16AM +1000, Nick Piggin wrote: > > > > > + count = ((sb->s_nr_dentry_unused + sb->s_nr_inodes_unused) / 100) > > > > > + * sysctl_vfs_cache_pressure; > > > > > > > > Do you think truncating in the divisions is at all a problem? It > > > > probably doesn't matter much I suppose. > > > > > > Same code as currently exists. IIRC, the reasoning is that if we've > > > got less that 100 objects to reclaim, then we're unlikely to be able > > > to free up any memory from the caches, anyway. > > > > Yeah, which is why I stop short of saying you should change it in > > this patch. > > > > But I think we should ensure things can get reclaimed eventually. > > 100 objects could be 100 slabs, which could be anything from > > half a meg to half a dozen. Multiplied by each of the caches. > > Could be significant in small systems. > > True, but usually there are busy objects in the dentry and inode > slabs, so it shouldn't be a significant issue. We can probably > address such problems if they can be demonstrated to be an issue in > a separate patch set.... I didn't want to say it is a problem with your patchset, I just thought of it when reviewing. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [PATCH 3/5] superblock: introduce per-sb cache shrinker infrastructure Date: Thu, 27 May 2010 14:24:53 +1000 Message-ID: <20100527042453.GI22536@laptop> References: <1274777588-21494-1-git-send-email-david@fromorbit.com> <1274777588-21494-4-git-send-email-david@fromorbit.com> <20100526164116.GD22536@laptop> <20100526231214.GB1395@dastard> <20100527021905.GG22536@laptop> <20100527040704.GJ12087@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, xfs@oss.sgi.com To: Dave Chinner Return-path: Content-Disposition: inline In-Reply-To: <20100527040704.GJ12087@dastard> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Thu, May 27, 2010 at 02:07:04PM +1000, Dave Chinner wrote: > On Thu, May 27, 2010 at 12:19:05PM +1000, Nick Piggin wrote: > > On Thu, May 27, 2010 at 09:12:14AM +1000, Dave Chinner wrote: > > > On Thu, May 27, 2010 at 02:41:16AM +1000, Nick Piggin wrote: > > > > > + count = ((sb->s_nr_dentry_unused + sb->s_nr_inodes_unused) / 100) > > > > > + * sysctl_vfs_cache_pressure; > > > > > > > > Do you think truncating in the divisions is at all a problem? It > > > > probably doesn't matter much I suppose. > > > > > > Same code as currently exists. IIRC, the reasoning is that if we've > > > got less that 100 objects to reclaim, then we're unlikely to be able > > > to free up any memory from the caches, anyway. > > > > Yeah, which is why I stop short of saying you should change it in > > this patch. > > > > But I think we should ensure things can get reclaimed eventually. > > 100 objects could be 100 slabs, which could be anything from > > half a meg to half a dozen. Multiplied by each of the caches. > > Could be significant in small systems. > > True, but usually there are busy objects in the dentry and inode > slabs, so it shouldn't be a significant issue. We can probably > address such problems if they can be demonstrated to be an issue in > a separate patch set.... I didn't want to say it is a problem with your patchset, I just thought of it when reviewing. -- 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