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 44A3FC77B73 for ; Wed, 31 May 2023 21:38:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230317AbjEaViw (ORCPT ); Wed, 31 May 2023 17:38:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230298AbjEaVig (ORCPT ); Wed, 31 May 2023 17:38:36 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7EB37E58 for ; Wed, 31 May 2023 14:38:10 -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 F385363F53 for ; Wed, 31 May 2023 21:36:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5102FC433D2; Wed, 31 May 2023 21:36:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1685569019; bh=lLsvXLyX8jEFLRHC4j8LUn5UPlRgmiADim4S8Ypvjng=; h=Date:To:From:Subject:From; b=Kw6fvgCWNYkPTW4GoZjUBW8n67BTcBB0xrpsOQcwklAQNzbp1kHff0/7U7JclTRat szV/VLoUSXR6N6vvbrUAhjSF3ZFKf9C01i1TRfYA//brESOZ2Ud8//8m/FME+4ofvf vR4q+RmzKuI09TSFIugQaqsorjYBXW9gj6EwvlTY= Date: Wed, 31 May 2023 14:36:58 -0700 To: mm-commits@vger.kernel.org, ying.huang@intel.com, vbabka@suse.cz, mgorman@techsingularity.net, penguin-kernel@I-love.SAKURA.ne.jp, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-page_alloc-dont-wake-kswapd-from-rmqueue-unless-__gfp_kswapd_reclaim-is-specified.patch added to mm-unstable branch Message-Id: <20230531213659.5102FC433D2@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/page_alloc: don't wake kswapd from rmqueue() unless __GFP_KSWAPD_RECLAIM is specified has been added to the -mm mm-unstable branch. Its filename is mm-page_alloc-dont-wake-kswapd-from-rmqueue-unless-__gfp_kswapd_reclaim-is-specified.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-dont-wake-kswapd-from-rmqueue-unless-__gfp_kswapd_reclaim-is-specified.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: Tetsuo Handa Subject: mm/page_alloc: don't wake kswapd from rmqueue() unless __GFP_KSWAPD_RECLAIM is specified Date: Sun, 14 May 2023 09:28:56 +0900 Commit 73444bc4d8f9 ("mm, page_alloc: do not wake kswapd with zone lock held") moved wakeup_kswapd() from steal_suitable_fallback() to rmqueue() using ZONE_BOOSTED_WATERMARK flag. Only allocation contexts that include ALLOC_KSWAPD (which corresponds to __GFP_KSWAPD_RECLAIM) should wake kswapd, for callers are supposed to remove __GFP_KSWAPD_RECLAIM if trying to hold pgdat->kswapd_wait has a risk of deadlock. But since zone->flags is a shared variable, a thread doing !__GFP_KSWAPD_RECLAIM allocation request might observe this flag being set immediately after another thread doing __GFP_KSWAPD_RECLAIM allocation request set this flag, causing possibility of deadlock. Link: https://lkml.kernel.org/r/c3c3dacf-dd3b-77c9-f96a-d0982b4b2a4f@I-love.SAKURA.ne.jp Fixes: 73444bc4d8f9 ("mm, page_alloc: do not wake kswapd with zone lock held") Signed-off-by: Tetsuo Handa Acked-by: Mel Gorman Cc: "Huang, Ying" Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/page_alloc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/page_alloc.c~mm-page_alloc-dont-wake-kswapd-from-rmqueue-unless-__gfp_kswapd_reclaim-is-specified +++ a/mm/page_alloc.c @@ -2863,7 +2863,8 @@ struct page *rmqueue(struct zone *prefer out: /* Separate test+clear to avoid unnecessary atomics */ - if (unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) { + if ((alloc_flags & ALLOC_KSWAPD) && + unlikely(test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags))) { clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags); wakeup_kswapd(zone, 0, 0, zone_idx(zone)); } _ Patches currently in -mm which might be from penguin-kernel@I-love.SAKURA.ne.jp are workingset-refactor-lru-refault-to-expose-refault-recency-check-fix.patch kasankmsan-remove-__gfp_kswapd_reclaim-usage-from-kasan-kmsan.patch mm-page_alloc-dont-wake-kswapd-from-rmqueue-unless-__gfp_kswapd_reclaim-is-specified.patch debugobjects-turn-off-debug_objects_enabled-from-debug_objects_oom.patch