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=-15.8 required=3.0 tests=BAYES_00,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 9AB51C433B4 for ; Mon, 12 Apr 2021 16:57:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E4F52611C9 for ; Mon, 12 Apr 2021 16:57:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E4F52611C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=natalenko.name Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 43BE26B006C; Mon, 12 Apr 2021 12:57:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3EB966B006E; Mon, 12 Apr 2021 12:57:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 28CAD6B0070; Mon, 12 Apr 2021 12:57:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0190.hostedemail.com [216.40.44.190]) by kanga.kvack.org (Postfix) with ESMTP id 05DBD6B006C for ; Mon, 12 Apr 2021 12:57:46 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 9F2CF8248D7C for ; Mon, 12 Apr 2021 16:57:46 +0000 (UTC) X-FDA: 78024321732.08.3F7DC91 Received: from vulcan.natalenko.name (vulcan.natalenko.name [104.207.131.136]) by imf12.hostedemail.com (Postfix) with ESMTP id 1AEEB13A for ; Mon, 12 Apr 2021 16:57:39 +0000 (UTC) Received: from localhost (kaktus.kanapka.ml [151.237.229.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by vulcan.natalenko.name (Postfix) with ESMTPSA id 634EBA2AF72; Mon, 12 Apr 2021 18:57:42 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1618246662; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=LdFy/WsqRV13J/Bu3JnHBX56utssyQ/cLHJjiDA2rn8=; b=nIE3wXy40y37nIc2Un3HjB7AQJvoP7Qc319exCQqFUEdkwyLzw2pPDCaKy4U121T4Q4Zoh YylzeRA+iPNTnNBnlX2vI8p/PpmNum9fp7l6yyX7gXnbUG0abahjpzyb812z9ImBw3oQBQ KWqzXh3Nqa8B/g++6JxiFDN2KmpTR/s= Date: Mon, 12 Apr 2021 18:57:41 +0200 From: Oleksandr Natalenko To: chukaiping Cc: mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm/compaction:let proactive compaction order configurable Message-ID: <20210412165741.shqududzlfhge7ff@spock.localdomain> References: <1618218330-50591-1-git-send-email-chukaiping@baidu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1618218330-50591-1-git-send-email-chukaiping@baidu.com> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 1AEEB13A X-Stat-Signature: op51miqoien6zrtxiohzgahdaw7ii1jm Received-SPF: none (natalenko.name>: No applicable sender policy available) receiver=imf12; identity=mailfrom; envelope-from=""; helo=vulcan.natalenko.name; client-ip=104.207.131.136 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1618246659-806530 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: Hello. On Mon, Apr 12, 2021 at 05:05:30PM +0800, chukaiping wrote: > Currently the proactive compaction order is fixed to > COMPACTION_HPAGE_ORDER(9), it's OK in most machines with lots of > normal 4KB memory, but it's too high for the machines with small > normal memory, for example the machines with most memory configured > as 1GB hugetlbfs huge pages. In these machines the max order of > free pages is often below 9, and it's always below 9 even with hard > compaction. This will lead to proactive compaction be triggered very > frequently. In these machines we only care about order of 3 or 4. > This patch export the oder to proc and let it configurable > by user, and the default value is still COMPACTION_HPAGE_ORDER. > > Signed-off-by: chukaiping > --- > include/linux/compaction.h | 1 + > kernel/sysctl.c | 10 ++++++++++ > mm/compaction.c | 7 ++++--- > 3 files changed, 15 insertions(+), 3 deletions(-) > > diff --git a/include/linux/compaction.h b/include/linux/compaction.h > index ed4070e..151ccd1 100644 > --- a/include/linux/compaction.h > +++ b/include/linux/compaction.h > @@ -83,6 +83,7 @@ static inline unsigned long compact_gap(unsigned int order) > #ifdef CONFIG_COMPACTION > extern int sysctl_compact_memory; > extern unsigned int sysctl_compaction_proactiveness; > +extern unsigned int sysctl_compaction_order; > extern int sysctl_compaction_handler(struct ctl_table *table, int write, > void *buffer, size_t *length, loff_t *ppos); > extern int sysctl_extfrag_threshold; > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 62fbd09..277df31 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -114,6 +114,7 @@ > static int __maybe_unused neg_one = -1; > static int __maybe_unused two = 2; > static int __maybe_unused four = 4; > +static int __maybe_unused ten = 10; ^^ does the upper limit have to be hard-coded like this? > static unsigned long zero_ul; > static unsigned long one_ul = 1; > static unsigned long long_max = LONG_MAX; > @@ -2871,6 +2872,15 @@ int proc_do_static_key(struct ctl_table *table, int write, > .extra2 = &one_hundred, > }, > { > + .procname = "compaction_order", > + .data = &sysctl_compaction_order, > + .maxlen = sizeof(sysctl_compaction_order), > + .mode = 0644, > + .proc_handler = proc_dointvec_minmax, > + .extra1 = SYSCTL_ZERO, I wonder what happens if this knob is set to 0. Have you tested such a corner case? > + .extra2 = &ten, > + }, > + { > .procname = "extfrag_threshold", > .data = &sysctl_extfrag_threshold, > .maxlen = sizeof(int), > diff --git a/mm/compaction.c b/mm/compaction.c > index e04f447..a192996 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -1925,16 +1925,16 @@ static bool kswapd_is_running(pg_data_t *pgdat) > > /* > * A zone's fragmentation score is the external fragmentation wrt to the > - * COMPACTION_HPAGE_ORDER. It returns a value in the range [0, 100]. > + * sysctl_compaction_order. It returns a value in the range [0, 100]. > */ > static unsigned int fragmentation_score_zone(struct zone *zone) > { > - return extfrag_for_order(zone, COMPACTION_HPAGE_ORDER); > + return extfrag_for_order(zone, sysctl_compaction_order); > } > > /* > * A weighted zone's fragmentation score is the external fragmentation > - * wrt to the COMPACTION_HPAGE_ORDER scaled by the zone's size. It > + * wrt to the sysctl_compaction_order scaled by the zone's size. It > * returns a value in the range [0, 100]. > * > * The scaling factor ensures that proactive compaction focuses on larger > @@ -2666,6 +2666,7 @@ static void compact_nodes(void) > * background. It takes values in the range [0, 100]. > */ > unsigned int __read_mostly sysctl_compaction_proactiveness = 20; > +unsigned int __read_mostly sysctl_compaction_order = COMPACTION_HPAGE_ORDER; > > /* > * This is the entry point for compacting all nodes via > -- > 1.7.1 > -- Oleksandr Natalenko (post-factum)