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 9CCCBC77B7A for ; Fri, 19 May 2023 21:40:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229523AbjESVkB (ORCPT ); Fri, 19 May 2023 17:40:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229449AbjESVj6 (ORCPT ); Fri, 19 May 2023 17:39:58 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 519BB101 for ; Fri, 19 May 2023 14:39:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E1999643FF for ; Fri, 19 May 2023 21:39:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 496C7C433EF; Fri, 19 May 2023 21:39:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1684532396; bh=mlYSjc558Oi7oxtJVfgLBTxmj5IfSGMUu3L9pgPD2MQ=; h=Date:To:From:Subject:From; b=ZC32QrULk9H3Hlsz6X2/ssKS1aF989bhz4bJEOX3ylgAuAqqQN8G/ZQhsUJH73ock /or2mIdiMAwQviCVcdcBWJlSKebAnLdVRsUEadaqEzhNms878JbOwqGY8/rAfNZPJo w1njqgAVV1uMWw5Z9rnrs4omjS5pbeCvIpnMVjXc= Date: Fri, 19 May 2023 14:39:55 -0700 To: mm-commits@vger.kernel.org, vbabka@suse.cz, mhocko@suse.com, mgorman@techsingularity.net, hannes@cmpxchg.org, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-compaction-simplify-should_compact_retry.patch added to mm-unstable branch Message-Id: <20230519213956.496C7C433EF@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: compaction: simplify should_compact_retry() has been added to the -mm mm-unstable branch. Its filename is mm-compaction-simplify-should_compact_retry.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-simplify-should_compact_retry.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Johannes Weiner Subject: mm: compaction: simplify should_compact_retry() Date: Fri, 19 May 2023 14:39:56 +0200 The different branches for retry are unnecessarily complicated. There are really only three outcomes: progress (retry n times), skipped (retry if reclaim can help), failed (retry with higher priority). Rearrange the branches and the retry counter to make it simpler. Link: https://lkml.kernel.org/r/20230519123959.77335-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Cc: Mel Gorman Cc: Michal Hocko Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/page_alloc.c | 53 +++++++++++++--------------------------------- 1 file changed, 16 insertions(+), 37 deletions(-) --- a/mm/page_alloc.c~mm-compaction-simplify-should_compact_retry +++ a/mm/page_alloc.c @@ -3510,16 +3510,22 @@ should_compact_retry(struct alloc_contex * Compaction managed to coalesce some page blocks, but the * allocation failed presumably due to a race. Retry some. */ - if (compact_result == COMPACT_SUCCESS) - (*compaction_retries)++; + if (compact_result == COMPACT_SUCCESS) { + /* + * !costly requests are much more important than + * __GFP_RETRY_MAYFAIL costly ones because they are de + * facto nofail and invoke OOM killer to move on while + * costly can fail and users are ready to cope with + * that. 1/4 retries is rather arbitrary but we would + * need much more detailed feedback from compaction to + * make a better decision. + */ + if (order > PAGE_ALLOC_COSTLY_ORDER) + max_retries /= 4; - /* - * All zones were scanned completely and still no result. It - * doesn't really make much sense to retry except when the - * failure could be caused by insufficient priority - */ - if (compact_result == COMPACT_COMPLETE) - goto check_priority; + ret = ++(*compaction_retries) <= max_retries; + goto out; + } /* * Compaction was skipped due to a lack of free order-0 @@ -3531,35 +3537,8 @@ should_compact_retry(struct alloc_contex } /* - * If compaction backed due to being deferred, due to - * contended locks in async mode, or due to scanners meeting - * after a partial scan, retry with increased priority. - */ - if (compact_result == COMPACT_DEFERRED || - compact_result == COMPACT_CONTENDED || - compact_result == COMPACT_PARTIAL_SKIPPED) - goto check_priority; - - /* - * !costly requests are much more important than __GFP_RETRY_MAYFAIL - * costly ones because they are de facto nofail and invoke OOM - * killer to move on while costly can fail and users are ready - * to cope with that. 1/4 retries is rather arbitrary but we - * would need much more detailed feedback from compaction to - * make a better decision. - */ - if (order > PAGE_ALLOC_COSTLY_ORDER) - max_retries /= 4; - if (*compaction_retries <= max_retries) { - ret = true; - goto out; - } - - /* - * Make sure there are attempts at the highest priority if we exhausted - * all retries or failed at the lower priorities. + * Compaction failed. Retry with increasing priority. */ -check_priority: min_priority = (order > PAGE_ALLOC_COSTLY_ORDER) ? MIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY; _ Patches currently in -mm which might be from hannes@cmpxchg.org are mm-compaction-remove-compaction-result-helpers.patch mm-compaction-simplify-should_compact_retry.patch mm-compaction-refactor-__compaction_suitable.patch mm-compaction-remove-unnecessary-is_via_compact_memory-checks.patch mm-compaction-drop-redundant-watermark-check-in-compaction_zonelist_suitable.patch