From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f198.google.com (mail-io0-f198.google.com [209.85.223.198]) by kanga.kvack.org (Postfix) with ESMTP id 92A146B025E for ; Wed, 8 Jun 2016 12:34:56 -0400 (EDT) Received: by mail-io0-f198.google.com with SMTP id d4so20807419iod.3 for ; Wed, 08 Jun 2016 09:34:56 -0700 (PDT) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTP id qo11si2066271pab.106.2016.06.08.09.34.49 for ; Wed, 08 Jun 2016 09:34:55 -0700 (PDT) Subject: Re: [PATCH 1/1] mm/swap.c: flush lru_add pvecs on compound page arrival References: <1465396537-17277-1-git-send-email-lukasz.odzioba@intel.com> <57583A49.30809@intel.com> <20160608160653.GB21838@dhcp22.suse.cz> From: Dave Hansen Message-ID: <575848F9.2060501@intel.com> Date: Wed, 8 Jun 2016 09:34:01 -0700 MIME-Version: 1.0 In-Reply-To: <20160608160653.GB21838@dhcp22.suse.cz> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Lukasz Odzioba , linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, aarcange@redhat.com, vdavydov@parallels.com, mingli199x@qq.com, minchan@kernel.org, lukasz.anaczkowski@intel.com, "Shutemov, Kirill" On 06/08/2016 09:06 AM, Michal Hocko wrote: >> > Do we have any statistics that tell us how many pages are sitting the >> > lru pvecs? Although this helps the problem overall, don't we still have >> > a problem with memory being held in such an opaque place? > Is it really worth bothering when we are talking about 56kB per CPU > (after this patch)? That was the logic why we didn't have it up until now: we didn't *expect* it to get large. A code change blew it up by 512x, and we had no instrumentation to tell us where all the memory went. I guess we don't have any other ways to group pages than compound pages, and _that_ one is covered now... for one of the 5 classes of pvecs. Is there a good reason we don't have to touch the other 4 pagevecs, btw? -- 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