From nobody Sat Jan 3 06:37:40 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57881E7C4E9 for ; Wed, 4 Oct 2023 19:07:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245400AbjJDTHn (ORCPT ); Wed, 4 Oct 2023 15:07:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343888AbjJDTHY (ORCPT ); Wed, 4 Oct 2023 15:07:24 -0400 Received: from 66-220-144-178.mail-mxout.facebook.com (66-220-144-178.mail-mxout.facebook.com [66.220.144.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F370430ED for ; Wed, 4 Oct 2023 12:03:15 -0700 (PDT) Received: by devbig1114.prn1.facebook.com (Postfix, from userid 425415) id B20EFD08BFFD; Wed, 4 Oct 2023 12:03:02 -0700 (PDT) From: Stefan Roesch To: kernel-team@fb.com Cc: shr@devkernel.io, akpm@linux-foundation.org, david@redhat.com, hannes@cmpxchg.org, riel@surriel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v1 2/4] mm/ksm: add sysfs knobs for advisor Date: Wed, 4 Oct 2023 12:02:47 -0700 Message-Id: <20231004190249.829015-3-shr@devkernel.io> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20231004190249.829015-1-shr@devkernel.io> References: <20231004190249.829015-1-shr@devkernel.io> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This adds four new knobs for the KSM advisor to influence its behaviour. The knobs are: - advisor_mode: 0: no advisor (default) 1: scan time advisor - advisor_min_pages: 500 (default) - advisor_max_pages: 5000 (default) - advisor_target_scan_time: 200 (default in seconds) The new values will take effect on the next scan round. Signed-off-by: Stefan Roesch --- mm/ksm.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) diff --git a/mm/ksm.c b/mm/ksm.c index c9edfb293024..12e70f806b2b 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -341,6 +341,14 @@ static void init_advisor(void) advisor_ctx.change =3D 0; } =20 +static void set_advisor_defaults(void) +{ + if (ksm_advisor =3D=3D KSM_ADVISOR_NONE) + ksm_thread_pages_to_scan =3D DEFAULT_PAGES_TO_SCAN; + else if (ksm_advisor =3D=3D KSM_ADVISOR_SCAN_TIME) + ksm_thread_pages_to_scan =3D ksm_advisor_min_pages; +} + /* * Use previous scan time if available, otherwise use current scan time as= an * approximation for the previous scan time. @@ -3692,6 +3700,102 @@ static ssize_t smart_scan_store(struct kobject *kob= j, } KSM_ATTR(smart_scan); =20 +static ssize_t advisor_mode_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%u\n", ksm_advisor); +} + +static ssize_t advisor_mode_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, + size_t count) +{ + unsigned int mode; + int err; + + err =3D kstrtouint(buf, 10, &mode); + if (err) + return -EINVAL; + if (mode > KSM_ADVISOR_LAST) + return -EINVAL; + + /* Set advisor default values */ + ksm_advisor =3D mode; + init_advisor(); + set_advisor_defaults(); + + return count; +} +KSM_ATTR(advisor_mode); + +static ssize_t advisor_min_pages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_min_pages); +} + +static ssize_t advisor_min_pages_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err =3D kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + + ksm_advisor_min_pages =3D value; + return count; +} +KSM_ATTR(advisor_min_pages); + +static ssize_t advisor_max_pages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_max_pages); +} + +static ssize_t advisor_max_pages_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err =3D kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + + ksm_advisor_max_pages =3D value; + return count; +} +KSM_ATTR(advisor_max_pages); + +static ssize_t advisor_target_scan_time_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", ksm_advisor_target_scan_time); +} + +static ssize_t advisor_target_scan_time_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int err; + unsigned long value; + + err =3D kstrtoul(buf, 10, &value); + if (err) + return -EINVAL; + if (value < 1) + return -EINVAL; + + ksm_advisor_target_scan_time =3D value; + return count; +} +KSM_ATTR(advisor_target_scan_time); + static struct attribute *ksm_attrs[] =3D { &sleep_millisecs_attr.attr, &pages_to_scan_attr.attr, @@ -3714,6 +3818,10 @@ static struct attribute *ksm_attrs[] =3D { &use_zero_pages_attr.attr, &general_profit_attr.attr, &smart_scan_attr.attr, + &advisor_mode_attr.attr, + &advisor_min_pages_attr.attr, + &advisor_max_pages_attr.attr, + &advisor_target_scan_time_attr.attr, NULL, }; =20 --=20 2.39.3