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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 89E77C433E0 for ; Wed, 3 Jun 2020 23:03:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 413B0221FB for ; Wed, 3 Jun 2020 23:03:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="EE+DI4Ha" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 413B0221FB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DE14E28007D; Wed, 3 Jun 2020 19:03:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D90EF28006C; Wed, 3 Jun 2020 19:03:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CD15528007D; Wed, 3 Jun 2020 19:03:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0122.hostedemail.com [216.40.44.122]) by kanga.kvack.org (Postfix) with ESMTP id B793E28006C for ; Wed, 3 Jun 2020 19:03:15 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 7CD1C181AEF09 for ; Wed, 3 Jun 2020 23:03:15 +0000 (UTC) X-FDA: 76889428350.24.mint27_397cab9a89d60 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 4B89A1A4A7 for ; Wed, 3 Jun 2020 23:03:15 +0000 (UTC) X-HE-Tag: mint27_397cab9a89d60 X-Filterd-Recvd-Size: 4262 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Wed, 3 Jun 2020 23:03:14 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E3F37221F7; Wed, 3 Jun 2020 23:03:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591225394; bh=0Y+VPlTSVox+pD+UjqwiTQDTLT5PpOKK0HX6pQ3pOKA=; h=Date:From:To:Subject:In-Reply-To:From; b=EE+DI4Hau1oKYX2iLATwVIq+alglreJZLYuEheKeV8R2Eq1O7UX6x3gNT1SI2larD Rkf0fCQFPXiDHOIHeNRta7QwFtAI1QOIwMJNjfZW1STUPheal+nxppTA+fqs9jD0gs TnCgo92w+p7r8TPeFtF7sjofFEtIiGQeshOAfxok= Date: Wed, 03 Jun 2020 16:03:13 -0700 From: Andrew Morton To: akpm@linux-foundation.org, hannes@cmpxchg.org, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, mhocko@suse.com, minchan@kernel.org, mm-commits@vger.kernel.org, riel@surriel.com, torvalds@linux-foundation.org Subject: [patch 116/131] mm: vmscan: limit the range of LRU type balancing Message-ID: <20200603230313.XgJ1Xx2cn%akpm@linux-foundation.org> In-Reply-To: <20200603155549.e041363450869eaae4c7f05b@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 4B89A1A4A7 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Johannes Weiner Subject: mm: vmscan: limit the range of LRU type balancing When LRU cost only shows up on one list, we abruptly stop scanning that list altogether. That's an extreme reaction: by the time the other list starts thrashing and the pendulum swings back, we may have no recent age information on the first list anymore, and we could have significant latencies until the scanner has caught up. Soften this change in the feedback system by ensuring that no list receives less than a third of overall pressure, and only distribute the other 66% according to LRU cost. This ensures that we maintain a minimum rate of aging on the entire workingset while it's being pressured, while still allowing a generous rate of convergence when the relative sizes of the lists need to adjust. Link: http://lkml.kernel.org/r/20200520232525.798933-15-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: Minchan Kim Cc: Rik van Riel Signed-off-by: Andrew Morton --- mm/vmscan.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) --- a/mm/vmscan.c~mm-vmscan-limit-the-range-of-lru-type-balancing +++ a/mm/vmscan.c @@ -2237,12 +2237,11 @@ static void get_scan_count(struct lruvec unsigned long *nr) { struct mem_cgroup *memcg = lruvec_memcg(lruvec); + unsigned long anon_cost, file_cost, total_cost; int swappiness = mem_cgroup_swappiness(memcg); u64 fraction[2]; u64 denominator = 0; /* gcc */ - unsigned long anon_prio, file_prio; enum scan_balance scan_balance; - unsigned long totalcost; unsigned long ap, fp; enum lru_list lru; @@ -2301,17 +2300,22 @@ static void get_scan_count(struct lruvec * the relative IO cost of bringing back a swapped out * anonymous page vs reloading a filesystem page (swappiness). * + * Although we limit that influence to ensure no list gets + * left behind completely: at least a third of the pressure is + * applied, before swappiness. + * * With swappiness at 100, anon and file have equal IO cost. */ - anon_prio = swappiness; - file_prio = 200 - anon_prio; + total_cost = sc->anon_cost + sc->file_cost; + anon_cost = total_cost + sc->anon_cost; + file_cost = total_cost + sc->file_cost; + total_cost = anon_cost + file_cost; - totalcost = sc->anon_cost + sc->file_cost; - ap = anon_prio * (totalcost + 1); - ap /= sc->anon_cost + 1; + ap = swappiness * (total_cost + 1); + ap /= anon_cost + 1; - fp = file_prio * (totalcost + 1); - fp /= sc->file_cost + 1; + fp = (200 - swappiness) * (total_cost + 1); + fp /= file_cost + 1; fraction[0] = ap; fraction[1] = fp; _