From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 581E7EDE99F for ; Thu, 14 Sep 2023 10:03:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237853AbjINKDt (ORCPT ); Thu, 14 Sep 2023 06:03:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237747AbjINKDr (ORCPT ); Thu, 14 Sep 2023 06:03:47 -0400 Received: from outbound-smtp55.blacknight.com (outbound-smtp55.blacknight.com [46.22.136.239]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C49881BE3 for ; Thu, 14 Sep 2023 03:03:42 -0700 (PDT) Received: from mail.blacknight.com (pemlinmail05.blacknight.ie [81.17.254.26]) by outbound-smtp55.blacknight.com (Postfix) with ESMTPS id ECF89FAC41 for ; Thu, 14 Sep 2023 11:03:40 +0100 (IST) Received: (qmail 9226 invoked from network); 14 Sep 2023 10:03:40 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.197.19]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 14 Sep 2023 10:03:40 -0000 Date: Thu, 14 Sep 2023 11:03:39 +0100 From: Mel Gorman To: Johannes Weiner Cc: Andrew Morton , Vlastimil Babka , Miaohe Lin , Kefeng Wang , Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/6] mm: page_alloc: fix move_freepages_block() range error Message-ID: <20230914100339.3dhgvsc6aprb5bbx@techsingularity.net> References: <20230911195023.247694-1-hannes@cmpxchg.org> <20230911195023.247694-5-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20230911195023.247694-5-hannes@cmpxchg.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 11, 2023 at 03:41:45PM -0400, Johannes Weiner wrote: > When a block is partially outside the zone of the cursor page, the > function cuts the range to the pivot page instead of the zone > start. This can leave large parts of the block behind, which > encourages incompatible page mixing down the line (ask for one type, > get another), and thus long-term fragmentation. > > This triggers reliably on the first block in the DMA zone, whose > start_pfn is 1. The block is stolen, but everything before the pivot > page (which was often hundreds of pages) is left on the old list. > > Signed-off-by: Johannes Weiner Oops Acked-by: Mel Gorman -- Mel Gorman SUSE Labs