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 B6825C433FE for ; Fri, 25 Mar 2022 01:33:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356287AbiCYBfM (ORCPT ); Thu, 24 Mar 2022 21:35:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39212 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353973AbiCYBeh (ORCPT ); Thu, 24 Mar 2022 21:34:37 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5A6EBF52C for ; Thu, 24 Mar 2022 18:32:27 -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 67972608C1 for ; Fri, 25 Mar 2022 01:32:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCBD9C340ED; Fri, 25 Mar 2022 01:32:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648171946; bh=xB0JzElTtfw7F8YCQ1KvQLg6sOnQ5HkwlyxpE3hVU9U=; h=Date:To:From:Subject:From; b=ePb0ymnprTLiGKIx2sGF2KmaXGBDdIS47A/i5zAWI2sxXsOEncD03WYjYToMonsB0 hL+i8zVyVChCu3OVr6Pj6IaHh7brvZI9XOVXCmeOrKr7UVwFeHQp3IiVjMGOQMfwcf mdCqRBvw33ba5pwz2Njot01TUiwuFjrjuVkBfUgg= Date: Thu, 24 Mar 2022 18:32:26 -0700 To: mm-commits@vger.kernel.org, yuzhao@google.com, minchan@kernel.org, iamjoonsoo.kim@lge.com, cgel.zte@gmail.com, hannes@cmpxchg.org, akpm@linux-foundation.org From: Andrew Morton Subject: [merged] mm-page_io-fix-psi-memory-pressure-error-on-cold-swapins.patch removed from -mm tree Message-Id: <20220325013226.BCBD9C340ED@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_io: fix psi memory pressure error on cold swapins has been removed from the -mm tree. Its filename was mm-page_io-fix-psi-memory-pressure-error-on-cold-swapins.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Johannes Weiner Subject: mm: page_io: fix psi memory pressure error on cold swapins Once upon a time, all swapins counted toward memory pressure[1]. Then Joonsoo introduced workingset detection for anonymous pages and we gained the ability to distinguish hot from cold swapins[2][3]. But we failed to update swap_readpage() accordingly, and now we account partial memory pressure in the swapin path of cold memory. Not for all situations - which adds more inconsistency: paths using the conventional submit_bio() and lock_page() route will not see much pressure - unless storage itself is heavily congested and the bio submissions stall. ZRAM and ZSWAP do most of the work directly from swap_readpage() and will see all swapins reflected as pressure. IOW, a workload doing cold swapins could see little to no pressure reported with on-disk swap, but potentially high pressure with a zram or zswap backend. That confuses any psi-based health monitoring, load shedding, proactive reclaim, or userspace OOM killing schemes that might be in place for the workload. Restore consistency by making all swapin stall accounting conditional on the page actually being part of the workingset. [1] commit 937790699be9 ("mm/page_io.c: annotate refault stalls from swap_readpage") [2] commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") [3] commit cad8320b4b39 ("mm/swap: don't SetPageWorkingset unconditionally during swapin") Link: https://lkml.kernel.org/r/20220214214921.419687-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reported-by: CGEL Acked-by: Minchan Kim Cc: Joonsoo Kim Cc: Yu Zhao Signed-off-by: Andrew Morton --- mm/page_io.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/mm/page_io.c~mm-page_io-fix-psi-memory-pressure-error-on-cold-swapins +++ a/mm/page_io.c @@ -359,6 +359,7 @@ int swap_readpage(struct page *page, boo struct bio *bio; int ret = 0; struct swap_info_struct *sis = page_swap_info(page); + bool workingset = PageWorkingset(page); unsigned long pflags; VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page); @@ -370,7 +371,8 @@ int swap_readpage(struct page *page, boo * or the submitting cgroup IO-throttled, submission can be a * significant part of overall IO time. */ - psi_memstall_enter(&pflags); + if (workingset) + psi_memstall_enter(&pflags); delayacct_swapin_start(); if (frontswap_load(page) == 0) { @@ -433,7 +435,8 @@ int swap_readpage(struct page *page, boo bio_put(bio); out: - psi_memstall_leave(&pflags); + if (workingset) + psi_memstall_leave(&pflags); delayacct_swapin_end(); return ret; } _ Patches currently in -mm which might be from hannes@cmpxchg.org are mm-madvise-madv_dontneed_locked.patch