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 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 D473DC433DF for ; Wed, 3 Jun 2020 22:58:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 95761208C9 for ; Wed, 3 Jun 2020 22:58:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="tmYFxY5P" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 95761208C9 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 3D02B28002B; Wed, 3 Jun 2020 18:58:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 38040280003; Wed, 3 Jun 2020 18:58:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2BD1A28002B; Wed, 3 Jun 2020 18:58:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0034.hostedemail.com [216.40.44.34]) by kanga.kvack.org (Postfix) with ESMTP id 0E25F280003 for ; Wed, 3 Jun 2020 18:58:51 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id D2029180AD806 for ; Wed, 3 Jun 2020 22:58:50 +0000 (UTC) X-FDA: 76889417220.21.hot89_12fbd76a17a2e Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id B65D0180442C0 for ; Wed, 3 Jun 2020 22:58:50 +0000 (UTC) X-HE-Tag: hot89_12fbd76a17a2e X-Filterd-Recvd-Size: 4362 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Wed, 3 Jun 2020 22:58:50 +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 54D9520FC3; Wed, 3 Jun 2020 22:58:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591225129; bh=JO/FByGMkgke8LKKh4+1TUVAgF+51+SEOqrXBXoRoWo=; h=Date:From:To:Subject:In-Reply-To:From; b=tmYFxY5Pxw8Yr2l4N0vGzyjBO8mTRj6kIAUiOMNpKaltz2VwKXkOOHCYhnPRMNTHl cABvC+UnQvnadguqa7RW004yXDxC+lU3L4EBaadb+WfE+mGDyPEZwdKj3ffoZZIZFu VFxYURBtMSE//WlF5MdYiJwJAyl4Ydwh9EHWK+tA= Date: Wed, 03 Jun 2020 15:58:48 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bhe@redhat.com, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, mgorman@techsingularity.net, mhocko@kernel.org, mm-commits@vger.kernel.org, rientjes@google.com, torvalds@linux-foundation.org Subject: [patch 039/131] mm/page_alloc.c: only tune sysctl_lowmem_reserve_ratio value once when changing it Message-ID: <20200603225848.zxB3-eNaM%akpm@linux-foundation.org> In-Reply-To: <20200603155549.e041363450869eaae4c7f05b@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: B65D0180442C0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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: Baoquan He Subject: mm/page_alloc.c: only tune sysctl_lowmem_reserve_ratio value once when changing it Patch series "improvements about lowmem_reserve and /proc/zoneinfo", v2. This patch (of 3): 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. Link: http://lkml.kernel.org/r/20200402140113.3696-1-bhe@redhat.com Link: http://lkml.kernel.org/r/20200402140113.3696-2-bhe@redhat.com Signed-off-by: Baoquan He Cc: Joonsoo Kim Cc: Michal Hocko Cc: Baoquan He Cc: Mel Gorman Cc: David Rientjes Signed-off-by: Andrew Morton --- mm/page_alloc.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/mm/page_alloc.c~mm-page_allocc-only-tune-sysctl_lowmem_reserve_ratio-value-once-when-changing-it +++ a/mm/page_alloc.c @@ -7704,8 +7704,7 @@ static void setup_per_zone_lowmem_reserv 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] = @@ -7970,7 +7969,15 @@ int sysctl_min_slab_ratio_sysctl_handler 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; } _