From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f173.google.com (mail-pf0-f173.google.com [209.85.192.173]) by kanga.kvack.org (Postfix) with ESMTP id CA84482963 for ; Wed, 3 Feb 2016 17:53:11 -0500 (EST) Received: by mail-pf0-f173.google.com with SMTP id 65so21551384pfd.2 for ; Wed, 03 Feb 2016 14:53:11 -0800 (PST) Received: from mga14.intel.com (mga14.intel.com. [192.55.52.115]) by mx.google.com with ESMTP id c8si11981001pat.62.2016.02.03.14.53.11 for ; Wed, 03 Feb 2016 14:53:11 -0800 (PST) Date: Thu, 4 Feb 2016 01:53:04 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCH 4/4] thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers Message-ID: <20160203225304.GB22605@black.fi.intel.com> References: <1454512459-94334-1-git-send-email-kirill.shutemov@linux.intel.com> <1454512459-94334-5-git-send-email-kirill.shutemov@linux.intel.com> <56B21FC9.9040009@intel.com> <20160203144316.f01573516f186071bb2cf1bf@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160203144316.f01573516f186071bb2cf1bf@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Dave Hansen , Andrea Arcangeli , Hugh Dickins , Mel Gorman , Rik van Riel , Vlastimil Babka , Christoph Lameter , Naoya Horiguchi , Steve Capper , "Aneesh Kumar K.V" , Johannes Weiner , Michal Hocko , Jerome Marchand , Sasha Levin , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Wed, Feb 03, 2016 at 02:43:16PM -0800, Andrew Morton wrote: > On Wed, 3 Feb 2016 07:42:01 -0800 Dave Hansen wrote: > > > On 02/03/2016 07:14 AM, Kirill A. Shutemov wrote: > > > But the new variant is somewhat slower. Current helpers iterates over > > > VMAs the compound page is mapped to, and then over ptes within this VMA. > > > New helpers iterates over small page, then over VMA the small page > > > mapped to, and only then find relevant pte. > > > > The code simplification here is really attractive. Can you quantify > > what the slowdown is? Is it noticeable, or would it be in the noise > > during all the other stuff that happens under memory pressure? > > yup. It is not really clear, how to quantify this properly. Let me think more about it. > And the "more testing is required" is a bit worrisome. Is this > code really ready for getting pounded upon in -next? By now it survived 5+ hours of fuzzing in 16 VM in parallel. I'll continue with other tests tomorrow. -- Kirill A. Shutemov -- 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