From patchwork Thu Apr 2 14:01:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Baoquan He X-Patchwork-Id: 11470815 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 82F8414DD for ; Thu, 2 Apr 2020 14:01:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 50B6B20784 for ; Thu, 2 Apr 2020 14:01:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gvUdRufu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 50B6B20784 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 89C828E000A; Thu, 2 Apr 2020 10:01:31 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 872FD8E0007; Thu, 2 Apr 2020 10:01:31 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7B0948E000A; Thu, 2 Apr 2020 10:01:31 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0166.hostedemail.com [216.40.44.166]) by kanga.kvack.org (Postfix) with ESMTP id 686818E0007 for ; Thu, 2 Apr 2020 10:01:31 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 274B1181AC9BF for ; Thu, 2 Apr 2020 14:01:31 +0000 (UTC) X-FDA: 76663077582.30.bee54_d36858d25639 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,bhe@redhat.com,,RULES_HIT:30012:30051:30054:30070,0,RBL:205.139.110.61:@redhat.com:.lbl8.mailshell.net-62.18.0.100 66.10.201.10,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:23,LUA_SUMMARY:none X-HE-Tag: bee54_d36858d25639 X-Filterd-Recvd-Size: 4341 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-2.mimecast.com [205.139.110.61]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Thu, 2 Apr 2020 14:01:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585836090; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=26MBqTIy3VM6rKEvhuSVZBdiFAMRZ0dKsv4z+LdLChM=; b=gvUdRufuxwGr2lJ83S5S5WZucVGe5wuQ2NK2wO9BEzWbdRMuIqBq19KOoQH8BHukK240wI hyvHvbtwFTARqeVyh9ft91obpC4S4pQDMHdtEkH3Y7mTXgJRuVTFxJZZSUwafTqiHgQA7Z PrYCoGBsHmht8IP9/s6rNerGT1UVjm0= 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-256-hw1VebTMNkSo8S_JMaEvkA-1; Thu, 02 Apr 2020 10:01:24 -0400 X-MC-Unique: hw1VebTMNkSo8S_JMaEvkA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AF136107ACCC; Thu, 2 Apr 2020 14:01:22 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-36.pek2.redhat.com [10.72.12.36]) by smtp.corp.redhat.com (Postfix) with ESMTP id D8DD360BF1; Thu, 2 Apr 2020 14:01:19 +0000 (UTC) From: Baoquan He To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, iamjoonsoo.kim@lge.com, mhocko@kernel.org, bhe@redhat.com, mgorman@techsingularity.net, rientjes@google.com Subject: [PATCH v2 1/3] mm/page_alloc.c: only tune sysctl_lowmem_reserve_ratio value once when changing it Date: Thu, 2 Apr 2020 22:01:11 +0800 Message-Id: <20200402140113.3696-2-bhe@redhat.com> In-Reply-To: <20200402140113.3696-1-bhe@redhat.com> References: <20200402140113.3696-1-bhe@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 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: When people write to /proc/sys/vm/lowmem_reserve_ratio to change sysctl_lowmem_reserve_ratio[], setup_per_zone_lowmem_reserve() is called to recalculate all ->lowmem_reserve[] for each zone of all nodes as below: static void setup_per_zone_lowmem_reserve(void) { ... for_each_online_pgdat(pgdat) { for (j = 0; j < MAX_NR_ZONES; j++) { ... while (idx) { ... if (sysctl_lowmem_reserve_ratio[idx] < 1) { sysctl_lowmem_reserve_ratio[idx] = 0; lower_zone->lowmem_reserve[j] = 0; } else { ... } } } } Meanwhile, here, sysctl_lowmem_reserve_ratio[idx] will be tuned if its value is smaller than '1'. As we know, sysctl_lowmem_reserve_ratio[] is set for zone without regarding to which node it belongs to. That means the tuning will be done on all nodes, even though it has been done in the first node. And the tuning will be done too even when init_per_zone_wmark_min() calls setup_per_zone_lowmem_reserve(), where actually nobody tries to change sysctl_lowmem_reserve_ratio[]. So now move the tuning into lowmem_reserve_ratio_sysctl_handler(), to make code logic more reasonable. Signed-off-by: Baoquan He --- mm/page_alloc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ca1453204e66..c0c788798d8b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7840,8 +7840,7 @@ static void setup_per_zone_lowmem_reserve(void) idx--; lower_zone = pgdat->node_zones + idx; - if (sysctl_lowmem_reserve_ratio[idx] < 1) { - sysctl_lowmem_reserve_ratio[idx] = 0; + if (!sysctl_lowmem_reserve_ratio[idx]) { lower_zone->lowmem_reserve[j] = 0; } else { lower_zone->lowmem_reserve[j] = @@ -8106,7 +8105,15 @@ int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write, int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) { + int i; + proc_dointvec_minmax(table, write, buffer, length, ppos); + + for (i = 0; i < MAX_NR_ZONES; i++) { + if (sysctl_lowmem_reserve_ratio[i] < 1) + sysctl_lowmem_reserve_ratio[i] = 0; + } + setup_per_zone_lowmem_reserve(); return 0; }