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=-16.5 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,SPF_HELO_NONE,SPF_PASS 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 4C488C432BE for ; Sat, 7 Aug 2021 02:21:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 19E0661167 for ; Sat, 7 Aug 2021 02:21:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230137AbhHGCWH (ORCPT ); Fri, 6 Aug 2021 22:22:07 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:45199 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229510AbhHGCWG (ORCPT ); Fri, 6 Aug 2021 22:22:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628302908; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=Q+7cG7xhRyIP8KFqGqqBfTmxfpmvZcxdghzXKqssv0Y=; b=ZuFS64Eif3+t4sdatlaVOBHmi4Yxr1kAT22dFuOpjxl6xsP/A6t1EsZ2d73X8da/Lj/4AQ E9fsSs1LKSBDB4ucgPv9dqab7i4sDiq8qdt7zfSHXdbGpnbVtCpR1DaH76gt5+t7xLFGXh P4/su3cyO40R6pTIN3/4zQyVlmMWsjI= 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-8-PwD0IpJLOpqWA9RHngli0g-1; Fri, 06 Aug 2021 22:21:47 -0400 X-MC-Unique: PwD0IpJLOpqWA9RHngli0g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 587521853025; Sat, 7 Aug 2021 02:21:46 +0000 (UTC) Received: from localhost.localdomain.com (unknown [10.22.16.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id 46CF627C47; Sat, 7 Aug 2021 02:21:41 +0000 (UTC) From: Nico Pache To: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Cc: hannes@cmpxchg.org, npache@redhat.com, aquini@redhat.com, shakeelb@google.com, llong@redhat.com Subject: [PATCH v2] vm_swappiness=0 should still try to avoid swapping anon memory Date: Fri, 6 Aug 2021 22:21:29 -0400 Message-Id: <20210807022129.8842-1-npache@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since commit b91ac374346b ("mm: vmscan: enforce inactive:active ratio at the reclaim root") swappiness can start prematurely swapping anon memory. This is due to the assumption that refaulting anon should always allow the shrinker to target anon memory. Add a check for swappiness being >0 before indiscriminately targeting Anon. This does not completely disable swapping, but rather tames the refaulting aspect of the code that allows for the deactivating of anon memory. A similar solution may be possible in the get_scan_count() part of the code, which determines the reclaim pressure for each LRU; however I believe that kind of solution may be too aggressive, and not allow other parts of the code (like direct reclaim) from targeting the active_anon list. This way we stop the problem at the heart of what is causing the issue, with the least amount of interference in other code paths. Furthermore, shrink_lruvec can modify the reclaim pressure of each LRU, which may make the get_scan_count solution even trickier. Changelog: -v2: made this mem_cgroup specific so now it will work with v1, v2, and no cgroups. I've also touched up my commit log. Signed-off-by: Nico Pache --- mm/vmscan.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 4620df62f0ff..89d4e84011b7 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2909,8 +2909,9 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc) refaults = lruvec_page_state(target_lruvec, WORKINGSET_ACTIVATE_ANON); - if (refaults != target_lruvec->refaults[0] || - inactive_is_low(target_lruvec, LRU_INACTIVE_ANON)) + if (mem_cgroup_swappiness(sc->target_mem_cgroup) && + (refaults != target_lruvec->refaults[0] || + inactive_is_low(target_lruvec, LRU_INACTIVE_ANON))) sc->may_deactivate |= DEACTIVATE_ANON; else sc->may_deactivate &= ~DEACTIVATE_ANON; -- 2.31.1