From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o4R45A6C107926 for ; Wed, 26 May 2010 23:05:11 -0500 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 7300937A698 for ; Wed, 26 May 2010 21:07:33 -0700 (PDT) Received: from mail.internode.on.net (bld-mail17.adl2.internode.on.net [150.101.137.102]) by cuda.sgi.com with ESMTP id WFS2RKPsb45SmPTD for ; Wed, 26 May 2010 21:07:33 -0700 (PDT) Date: Thu, 27 May 2010 14:07:04 +1000 From: Dave Chinner Subject: Re: [PATCH 3/5] superblock: introduce per-sb cache shrinker infrastructure Message-ID: <20100527040704.GJ12087@dastard> 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> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100527021905.GG22536@laptop> 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: Nick Piggin 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 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.... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs