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 X-Spam-Level: X-Spam-Status: No, score=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 938B8C433DB for ; Mon, 15 Mar 2021 11:10:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6746164EAE for ; Mon, 15 Mar 2021 11:10:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229688AbhCOLKR (ORCPT ); Mon, 15 Mar 2021 07:10:17 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:53365 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229813AbhCOLKN (ORCPT ); Mon, 15 Mar 2021 07:10:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615806613; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=M8yuhBec4/2fTpsvveERpk7/R/kPqBZv9NR7tFdHJ5s=; b=O2S7+mpTdathAM7oVQLb13wI8uSAX+l0VXmlDyoT0OtqK1crl9XJCRWdypGB1dnK56xQfR Gm61RkE3VXDAqdAFVghqDNVZOGwvhLjQ/ZeZX2Eox+8EOqluHOUCDV/XS1SgNNIUiBMT2b xGgZ4+d1bI0VwwXFRazKXzmI5DcdKhU= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-449-eOGXBqH5N3WE6lUyP2O3xQ-1; Mon, 15 Mar 2021 07:10:09 -0400 X-MC-Unique: eOGXBqH5N3WE6lUyP2O3xQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9F1301074659; Mon, 15 Mar 2021 11:10:07 +0000 (UTC) Received: from [10.36.112.200] (ovpn-112-200.ams2.redhat.com [10.36.112.200]) by smtp.corp.redhat.com (Postfix) with ESMTP id 56F9A6C43A; Mon, 15 Mar 2021 11:10:05 +0000 (UTC) Subject: Re: [PATCH v4 1/4] mm,page_alloc: Bail out earlier on -ENOMEM in alloc_contig_migrate_range To: Oscar Salvador , Andrew Morton Cc: Vlastimil Babka , Michal Hocko , Muchun Song , Mike Kravetz , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20210310150853.13541-1-osalvador@suse.de> <20210310150853.13541-2-osalvador@suse.de> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Mon, 15 Mar 2021 12:10:04 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210310150853.13541-2-osalvador@suse.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10.03.21 16:08, Oscar Salvador wrote: > Currently, __alloc_contig_migrate_range can generate -EINTR, -ENOMEM or -EBUSY, > and report them down the chain. > The problem is that when migrate_pages() reports -ENOMEM, we keep going till we > exhaust all the try-attempts (5 at the moment) instead of bailing out. > > migrate_pages bails out right away on -ENOMEM because it is considered a fatal > error. Do the same here instead of keep going and retrying. > > Signed-off-by: Oscar Salvador > --- > mm/page_alloc.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 3e4b29ee2b1e..94467f1b85ff 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -8484,7 +8484,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc, > } > tries = 0; > } else if (++tries == 5) { > - ret = ret < 0 ? ret : -EBUSY; > + ret = -EBUSY; > break; > } > > @@ -8494,6 +8494,12 @@ static int __alloc_contig_migrate_range(struct compact_control *cc, > > ret = migrate_pages(&cc->migratepages, alloc_migration_target, > NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE); > + /* > + * On -ENOMEM, migrate_pages() bails out right away. It is pointless > + * to retry again over this error, so do the same here. > + */ > + if (ret == -ENOMEM) > + break; I would have thought we could also be able to get other fatal errors from migrate_pages(), but doesn't seem like it Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb