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=-21.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, PDS_TONAME_EQ_TOLOCAL_HDRS_LCASE,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 36791C433B4 for ; Mon, 26 Apr 2021 01:15:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0DE6E601FD for ; Mon, 26 Apr 2021 01:15:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231579AbhDZBQM (ORCPT ); Sun, 25 Apr 2021 21:16:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231403AbhDZBQM (ORCPT ); Sun, 25 Apr 2021 21:16:12 -0400 Received: from mail-pl1-x634.google.com (mail-pl1-x634.google.com [IPv6:2607:f8b0:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8E02AC061574 for ; Sun, 25 Apr 2021 18:15:31 -0700 (PDT) Received: by mail-pl1-x634.google.com with SMTP id y1so12388409plg.11 for ; Sun, 25 Apr 2021 18:15:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=zu1tvaF/aGOCv1iAh1BOxPzQNHj2L/j6d+DdJvsoiAc=; b=XZmisxmKvnaeGLCOxrJra5jpdVFpPUsBGH5NSR3g0JWh2RAeWvZSewUe2Gpk5XzJxF hAbvuVE/HFIDWSklE7NIC2NRdgEL4p5sEF1IQ0UkEDsKOqdszZ2n4wexrW3cod5rpGHs R9DkZe+ni8Q0JTa+vayM5b2zAzVUvE38/8xchX+BX3UuUHRUUD+Kj1NwY+PjxenDUu+Y pE+a99NUh+p59s/yrs94pUymkJoruptGBfMuWQB1X3/aC68LSuGMx5ZabdhMnW0IFEpq kJhbpcCoVc3X42bgKoZchc7Kb+HTPoaaFONpSVZewJhhIzDD5hvNLD4EebwJkb6cI+St Pg0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=zu1tvaF/aGOCv1iAh1BOxPzQNHj2L/j6d+DdJvsoiAc=; b=oacudOI9r7qosqnd8QoAfN4YJVPDKSweInAHmWLWVQPePR2DFVVPE4UYMNJHpxLzAh TlBhdnpGKA0agCu7gttJ9z0Jqzgml8f/rW1kK7Zv0GVd7tS/cgLjvkCIh/0S8+lMlCMw NI2yMB6jGzYO69rG2Khn4SLGTQu3oPhk/IQy+yuYqovbH36nvel422NsY/rFwNimdY7v swvWrGjnmaNpsscSA0D24XuamOf37Gk/p1J1Mp3WSBkagSBAB23cpN3c07XkSW2TZmQH 8z0/nM/lS8YjSXLkSqElwg2WnFwC6PHqmJx5ollOhRQAIs/wizSFMKLd9nJ0VB65S1id If0A== X-Gm-Message-State: AOAM5322y9owIMnG9uG9ZwJuqEuZx59Y/rc5BvnGOKITjvRXbBnWdAeL sxuqFkxwfKH6h6X45Yw9pC7XcA== X-Google-Smtp-Source: ABdhPJy+r40r/3pW+j5fLUQ/aMJ3Cn33sVjNff185pYOomtv6VfIxCbNZmkspwGyNYta+kjV97OuQQ== X-Received: by 2002:a17:903:304b:b029:eb:4cf:8321 with SMTP id u11-20020a170903304bb02900eb04cf8321mr15873865pla.40.1619399730738; Sun, 25 Apr 2021 18:15:30 -0700 (PDT) Received: from [2620:15c:17:3:f93a:1c09:9070:93a7] ([2620:15c:17:3:f93a:1c09:9070:93a7]) by smtp.gmail.com with ESMTPSA id 1sm9993254pjx.46.2021.04.25.18.15.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 25 Apr 2021 18:15:29 -0700 (PDT) Date: Sun, 25 Apr 2021 18:15:28 -0700 (PDT) From: David Rientjes To: chukaiping cc: mcgrof@kernel.org, keescook@chromium.org, yzaikin@google.com, akpm@linux-foundation.org, vbabka@suse.cz, nigupta@nvidia.com, bhe@redhat.com, khalid.aziz@oracle.com, iamjoonsoo.kim@lge.com, mateusznosek0@gmail.com, sh_def@163.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v3] mm/compaction:let proactive compaction order configurable In-Reply-To: <1619313662-30356-1-git-send-email-chukaiping@baidu.com> Message-ID: References: <1619313662-30356-1-git-send-email-chukaiping@baidu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sun, 25 Apr 2021, 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. > As asked in the review of the v1 of the patch, why is this not a userspace policy decision? If you are interested in order-3 or order-4 fragmentation, for whatever reason, you could periodically check /proc/buddyinfo and manually invoke compaction on the system. In other words, why does this need to live in the kernel? > Signed-off-by: chukaiping > Reported-by: kernel test robot > --- > > Changes in v3: > - change the min value of compaction_order to 1 because the fragmentation > index of order 0 is always 0 > - move the definition of max_buddy_zone into #ifdef CONFIG_COMPACTION > > Changes in v2: > - fix the compile error in ia64 and powerpc, move the initialization > of sysctl_compaction_order to kcompactd_init because > COMPACTION_HPAGE_ORDER is a variable in these architectures > - change the hard coded max order number from 10 to MAX_ORDER - 1 > > include/linux/compaction.h | 1 + > kernel/sysctl.c | 10 ++++++++++ > mm/compaction.c | 9 ++++++--- > 3 files changed, 17 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..e50f7d2 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -196,6 +196,7 @@ enum sysctl_writes_mode { > #endif /* CONFIG_SCHED_DEBUG */ > > #ifdef CONFIG_COMPACTION > +static int max_buddy_zone = MAX_ORDER - 1; > static int min_extfrag_threshold; > static int max_extfrag_threshold = 1000; > #endif > @@ -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_ONE, > + .extra2 = &max_buddy_zone, > + }, > + { > .procname = "extfrag_threshold", > .data = &sysctl_extfrag_threshold, > .maxlen = sizeof(int), > diff --git a/mm/compaction.c b/mm/compaction.c > index e04f447..70c0acd 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; > > /* > * This is the entry point for compacting all nodes via > @@ -2958,6 +2959,8 @@ static int __init kcompactd_init(void) > int nid; > int ret; > > + sysctl_compaction_order = COMPACTION_HPAGE_ORDER; > + > ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, > "mm/compaction:online", > kcompactd_cpu_online, NULL); > -- > 1.7.1 > >