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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 40F94C0650F for ; Fri, 2 Aug 2019 22:40:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 07B05206A3 for ; Fri, 2 Aug 2019 22:40:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="m1L2JM/O" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437251AbfHBWkA (ORCPT ); Fri, 2 Aug 2019 18:40:00 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:57654 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392504AbfHBWkA (ORCPT ); Fri, 2 Aug 2019 18:40:00 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x72McvgT004454; Fri, 2 Aug 2019 22:39:42 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=corp-2018-07-02; bh=TC+FvVGBj7qXtMenbMrq0locSq4RPx9eaTkqkGiQRPY=; b=m1L2JM/OMDW2n0WfQFY3LPGcIeqtXCva5LDPlsHXHDdJuc/MVSopGE/PoYJsSYbxUDjy jxnR4Gd1UZcJMjvsEnaYYKKqWE4LhYV2UDumzIkrEK3XmtjQ4mTB8ArgbaEi1WcbPHk8 sl0k930q2/W7pWSlZpfy+dzLe+LjQl+OBzDc8W6dsZbA/uBf1KvsD3PpYB3k+k+0ytlt Sg2ok6ekSZJ4nMoRKfg+1ynJEzeDbmr045oVsVjJBm4UhH4Koik3et1pQuppKrSU41JB Dp3fqD5KpB3m//DdkKvtjhdNw+HHiJ/d9UX6k6dyHGdRw2P67qer4H0rQ3ium0NXtf0+ kQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by aserp2120.oracle.com with ESMTP id 2u0ejq4qt3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 02 Aug 2019 22:39:42 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x72MbhOw062691; Fri, 2 Aug 2019 22:39:42 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 2u4vsj1upr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 02 Aug 2019 22:39:42 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x72Mdd7M022130; Fri, 2 Aug 2019 22:39:39 GMT Received: from monkey.oracle.com (/71.63.128.209) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 02 Aug 2019 15:39:39 -0700 From: Mike Kravetz To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Hillf Danton , Vlastimil Babka , Michal Hocko , Mel Gorman , Johannes Weiner , Andrea Arcangeli , David Rientjes , Andrew Morton , Mike Kravetz Subject: [PATCH 2/3] mm, compaction: raise compaction priority after it withdrawns Date: Fri, 2 Aug 2019 15:39:29 -0700 Message-Id: <20190802223930.30971-3-mike.kravetz@oracle.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190802223930.30971-1-mike.kravetz@oracle.com> References: <20190802223930.30971-1-mike.kravetz@oracle.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9337 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908020238 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9337 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908020238 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vlastimil Babka Mike Kravetz reports that "hugetlb allocations could stall for minutes or hours when should_compact_retry() would return true more often then it should. Specifically, this was in the case where compact_result was COMPACT_DEFERRED and COMPACT_PARTIAL_SKIPPED and no progress was being made." The problem is that the compaction_withdrawn() test in should_compact_retry() includes compaction outcomes that are only possible on low compaction priority, and results in a retry without increasing the priority. This may result in furter reclaim, and more incomplete compaction attempts. With this patch, compaction priority is raised when possible, or should_compact_retry() returns false. The COMPACT_SKIPPED result doesn't really fit together with the other outcomes in compaction_withdrawn(), as that's a result caused by insufficient order-0 pages, not due to low compaction priority. With this patch, it is moved to a new compaction_needs_reclaim() function, and for that outcome we keep the current logic of retrying if it looks like reclaim will be able to help. Reported-by: Mike Kravetz Signed-off-by: Vlastimil Babka Tested-by: Mike Kravetz --- include/linux/compaction.h | 22 +++++++++++++++++----- mm/page_alloc.c | 16 ++++++++++++---- 2 files changed, 29 insertions(+), 9 deletions(-) diff --git a/include/linux/compaction.h b/include/linux/compaction.h index 9569e7c786d3..4b898cdbdf05 100644 --- a/include/linux/compaction.h +++ b/include/linux/compaction.h @@ -129,11 +129,8 @@ static inline bool compaction_failed(enum compact_result result) return false; } -/* - * Compaction has backed off for some reason. It might be throttling or - * lock contention. Retrying is still worthwhile. - */ -static inline bool compaction_withdrawn(enum compact_result result) +/* Compaction needs reclaim to be performed first, so it can continue. */ +static inline bool compaction_needs_reclaim(enum compact_result result) { /* * Compaction backed off due to watermark checks for order-0 @@ -142,6 +139,16 @@ static inline bool compaction_withdrawn(enum compact_result result) if (result == COMPACT_SKIPPED) return true; + return false; +} + +/* + * Compaction has backed off for some reason after doing some work or none + * at all. It might be throttling or lock contention. Retrying might be still + * worthwhile, but with a higher priority if allowed. + */ +static inline bool compaction_withdrawn(enum compact_result result) +{ /* * If compaction is deferred for high-order allocations, it is * because sync compaction recently failed. If this is the case @@ -207,6 +214,11 @@ static inline bool compaction_failed(enum compact_result result) return false; } +static inline bool compaction_needs_reclaim(enum compact_result result) +{ + return false; +} + static inline bool compaction_withdrawn(enum compact_result result) { return true; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d3bb601c461b..af29c05e23aa 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3965,15 +3965,23 @@ should_compact_retry(struct alloc_context *ac, int order, int alloc_flags, if (compaction_failed(compact_result)) goto check_priority; + /* + * compaction was skipped because there are not enough order-0 pages + * to work with, so we retry only if it looks like reclaim can help. + */ + if (compaction_needs_reclaim(compact_result)) { + ret = compaction_zonelist_suitable(ac, order, alloc_flags); + goto out; + } + /* * make sure the compaction wasn't deferred or didn't bail out early * due to locks contention before we declare that we should give up. - * But do not retry if the given zonelist is not suitable for - * compaction. + * But the next retry should use a higher priority if allowed, so + * we don't just keep bailing out endlessly. */ if (compaction_withdrawn(compact_result)) { - ret = compaction_zonelist_suitable(ac, order, alloc_flags); - goto out; + goto check_priority; } /* -- 2.20.1