Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755002Ab2K2WJU (ORCPT ); Thu, 29 Nov 2012 17:09:20 -0500 Received: from ipmail05.adl6.internode.on.net ([150.101.137.143]:49690 "EHLO ipmail05.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753304Ab2K2WJQ (ORCPT ); Thu, 29 Nov 2012 17:09:16 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApIKAM/bt1B5LN4a/2dsb2JhbABEhUK0R4V7F3OCHgEBBAEOLBwPFAULCAMYLhQlAyETiAoFvyEUjCyDYGEDlgCQRYMGgVEk Date: Fri, 30 Nov 2012 09:09:14 +1100 From: Dave Chinner To: Andi Kleen Cc: glommer@parallels.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, xfs@oss.sgi.com Subject: Re: [RFC, PATCH 00/19] Numa aware LRU lists and shrinkers Message-ID: <20121129220914.GE6434@dastard> References: <1354058086-27937-1-git-send-email-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1582 Lines: 43 On Thu, Nov 29, 2012 at 11:02:24AM -0800, Andi Kleen wrote: > Dave Chinner writes: > > > > Comments, thoughts and flames all welcome. > > Doing the reclaim per CPU sounds like a big change in the VM balance. It's per node, not per CPU. And AFAICT, it hasn't changed the balance of page cache vs inode/dentry caches under general, global workloads at all. > Doesn't this invalidate some zone reclaim mode settings? No, because zone reclaim is per-node and the shrinkers now can reclaim just from a single node. i.e. the behaviour is now better suited to the aims of zone reclaim which is to free memory from a single, targetted node. Indeed, I removed a hack in the zone reclaim code that sprayed slab reclaim across the entire machine until sufficient objects had been freed from the target node.... > How did you validate all this? fakenuma setups, various workloads that generate even dentry/slab cache loadings across all nodes, adding page cache pressure on a single node, watching slab reclaim from a single node. that sort of thing. I haven't really done any performance testing other than "not obviously slower". There's no point optimising anything before there's any sort of agreement as to whether this is the right approach to take or not.... Cheers, Dave. -- Dave Chinner david@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/