From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f52.google.com (mail-pa0-f52.google.com [209.85.220.52]) by kanga.kvack.org (Postfix) with ESMTP id 8BF546B0036 for ; Thu, 4 Sep 2014 18:55:50 -0400 (EDT) Received: by mail-pa0-f52.google.com with SMTP id eu11so21079755pac.11 for ; Thu, 04 Sep 2014 15:55:50 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTP id qa6si564992pdb.55.2014.09.04.15.55.48 for ; Thu, 04 Sep 2014 15:55:49 -0700 (PDT) Message-ID: <5408ED7A.5010908@intel.com> Date: Thu, 04 Sep 2014 15:53:46 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: regression caused by cgroups optimization in 3.17-rc2 References: <54061505.8020500@sr71.net> <5406262F.4050705@intel.com> <54062F32.5070504@sr71.net> <20140904142721.GB14548@dhcp22.suse.cz> <5408CB2E.3080101@sr71.net> In-Reply-To: <5408CB2E.3080101@sr71.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen , Michal Hocko Cc: Johannes Weiner , Hugh Dickins , Tejun Heo , Linux-MM , Andrew Morton , Linus Torvalds , Vladimir Davydov , LKML On 09/04/2014 01:27 PM, Dave Hansen wrote: > On 09/04/2014 07:27 AM, Michal Hocko wrote: >> Ouch. free_pages_and_swap_cache completely kills the uncharge batching >> because it reduces it to PAGEVEC_SIZE batches. >> >> I think we really do not need PAGEVEC_SIZE batching anymore. We are >> already batching on tlb_gather layer. That one is limited so I think >> the below should be safe but I have to think about this some more. There >> is a risk of prolonged lru_lock wait times but the number of pages is >> limited to 10k and the heavy work is done outside of the lock. If this >> is really a problem then we can tear LRU part and the actual >> freeing/uncharging into a separate functions in this path. >> >> Could you test with this half baked patch, please? I didn't get to test >> it myself unfortunately. > > 3.16 settled out at about 11.5M faults/sec before the regression. This > patch gets it back up to about 10.5M, which is good. The top spinlock > contention in the kernel is still from the resource counter code via > mem_cgroup_commit_charge(), though. > > I'm running Johannes' patch now. This looks pretty good. The area where it plateaus (above 80 threads where hyperthreading kicks in) might be a bit slower than it was in 3.16, but that could easily be from other things. > https://www.sr71.net/~dave/intel/bb.html?1=3.16.0-rc4-g67b9d76/&2=3.17.0-rc3-g57b252f Feel free to add my Tested-by: -- 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