Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752734AbcDFRqJ (ORCPT ); Wed, 6 Apr 2016 13:46:09 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:38565 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751898AbcDFRqH (ORCPT ); Wed, 6 Apr 2016 13:46:07 -0400 Date: Wed, 6 Apr 2016 10:46:05 -0700 From: Andrew Morton To: Hugh Dickins Cc: Michal Hocko , Linus Torvalds , Johannes Weiner , Mel Gorman , David Rientjes , Tetsuo Handa , Joonsoo Kim , Hillf Danton , linux-mm@kvack.org, LKML , Michal Hocko Subject: Re: [PATCH 09/11] mm, compaction: Abstract compaction feedback to helpers Message-Id: <20160406104605.e6254b153f2ab5a26fd556e5@linux-foundation.org> In-Reply-To: References: <1459855533-4600-1-git-send-email-mhocko@kernel.org> <1459855533-4600-10-git-send-email-mhocko@kernel.org> <20160405165826.012236e79db7f396fda546a8@linux-foundation.org> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1843 Lines: 42 On Tue, 5 Apr 2016 17:55:39 -0700 (PDT) Hugh Dickins wrote: > > I ended up doing this: > > > > /* Checks for THP-specific high-order allocations */ > > if (!is_thp_allocation(gfp_mask, order)) > > migration_mode = MIGRATE_SYNC_LIGHT; > > > > /* > > * Checks for THP-specific high-order allocations and back off > > * if the the compaction backed off > > */ > > if (is_thp_allocation(gfp_mask) && compaction_withdrawn(compact_result)) > > goto nopage; > > You'll already have found that is_thp_allocation() needs the order too. > But then you had to drop a hunk out of his 10/11 also to fit with mine. > > What you've done may be just right, but I haven't had time to digest > Michal's changes yet (and not yet seen what happens to the PF_KTHREAD > distinction), so I think it will probably end up better if you take > his exactly as he tested and posted them, and drop my 30/31 and 31/31 > for now - I can resubmit them (or maybe drop 30 altogether) after I've > pondered and tested a little on top of Michal's. > > Huge tmpfs got along fine for many months without 30/31 and 31/31: 30 > is just for experimentation, and 31 to reduce the compaction stalls we > saw under some loads. Maybe I'll find that Michal's rework has changed > the balance there anyway, and something else or nothing at all needed. > > (The gfp_mask stuff was very confusing, and it's painful for me, how > ~__GFP_KSWAPD_RECLAIM gets used as a secret password to say "THP" and > how to angle compaction - or maybe it's all more straightforward now.) OK, thanks. I dropped huge-tmpfs-shmem_huge_gfpmask-and-shmem_recovery_gfpmask.patch and huge-tmpfs-no-kswapd-by-default-on-sync-allocations.patch and restored Michal's patches. > Many thanks for giving us both this quick exposure! I'll push all this into -next later today.