From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [PATCH 3/5] superblock: introduce per-sb cache shrinker infrastructure Date: Thu, 27 May 2010 14:07:04 +1000 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-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: Nick Piggin Return-path: Content-Disposition: inline In-Reply-To: <20100527021905.GG22536@laptop> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org 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 -- 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