From nobody Wed Dec 17 21:12:52 2025 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 02660C2FC1A for ; Thu, 17 Aug 2023 08:10:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348780AbjHQIJm (ORCPT ); Thu, 17 Aug 2023 04:09:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348752AbjHQIJG (ORCPT ); Thu, 17 Aug 2023 04:09:06 -0400 Received: from invmail4.hynix.com (exvmail4.hynix.com [166.125.252.92]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 20819210E for ; Thu, 17 Aug 2023 01:09:04 -0700 (PDT) X-AuditID: a67dfc5b-d85ff70000001748-d5-64ddd598af46 From: Byungchul Park To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: kernel_team@skhynix.com, akpm@linux-foundation.org, ying.huang@intel.com, namit@vmware.com, xhao@linux.alibaba.com, mgorman@techsingularity.net, hughd@google.com, willy@infradead.org, david@redhat.com, peterz@infradead.org, luto@kernel.org, dave.hansen@linux.intel.com Subject: [RFC v2 5/6] mm, migrc: Add a sysctl knob to enable/disable MIGRC mechanism Date: Thu, 17 Aug 2023 17:05:58 +0900 Message-Id: <20230817080559.43200-6-byungchul@sk.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230817080559.43200-1-byungchul@sk.com> References: <20230817080559.43200-1-byungchul@sk.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrFLMWRmVeSWpSXmKPExsXC9ZZnke6Mq3dTDNrmGVnMWb+GzeLFhnZG i6/rfzFbPP3Ux2JxedccNot7a/6zWpzftZbVYsfSfUwW13c9ZLQ43nuAyeL3D6DsnClWFidn TWZx4PVYsKnUY/MKLY/Fe14yeWxa1cnmsenTJHaPEzN+s3jsfGjpMe9koMf7fVfZPLb+svP4 vEnO4938t2wBPFFcNimpOZllqUX6dglcGXf/GRccEKrYMmEvcwPje74uRk4OCQETieN35zHB 2Ldm7mMDsdkE1CVu3PjJDGKLCJhJHGz9w97FyMXBLLCMSeLugXOsIAlhgRCJnw9awGwWAVWJ J93XwWxeAVOJ35sbmCGGykus3nAAyObg4AQatPmvKkhYCKjkw951rCAzJQTOsElcnvKQHaJe UuLgihssExh5FzAyrGIUyswry03MzDHRy6jMy6zQS87P3cQIDOFltX+idzB+uhB8iFGAg1GJ h9dh150UIdbEsuLK3EOMEhzMSiK8Pby3UoR4UxIrq1KL8uOLSnNSiw8xSnOwKInzGn0rTxES SE8sSc1OTS1ILYLJMnFwSjUwztn16LDMdu7/Ycu1d3hUcljkZDFn+jWF3jJcNevB5GdSv2oK lp1qjIpo+SffzJmQuj62+u5O+VfBfV2qc7bsitTfENnsPnV/Z27Lb4eLL9bcWno1XnXVoVCz Ey5G25t6Kw+vmae4W1Dk8+qLqwwT+S+k7VPhT03aHLniSjfTky0PvgYYGGhkK7EUZyQaajEX FScCADd7b45dAgAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrILMWRmVeSWpSXmKPExsXC5WfdrDvj6t0UgyN7NCzmrF/DZvFiQzuj xdf1v5gtnn7qY7E4PPckq8XlXXPYLO6t+c9qcX7XWlaLHUv3MVlc3/WQ0eJ47wEmi98/gLJz plhZnJw1mcWBz2PBplKPzSu0PBbvecnksWlVJ5vHpk+T2D1OzPjN4rHzoaXHvJOBHu/3XWXz WPziA5PH1l92Hp83yXm8m/+WLYA3issmJTUnsyy1SN8ugSvj7j/jggNCFVsm7GVuYHzP18XI ySEhYCJxa+Y+NhCbTUBd4saNn8wgtoiAmcTB1j/sXYxcHMwCy5gk7h44xwqSEBYIkfj5oAXM ZhFQlXjSfR3M5hUwlfi9uYEZYqi8xOoNB4BsDg5OoEGb/6qChIWASj7sXcc6gZFrASPDKkaR zLyy3MTMHFO94uyMyrzMCr3k/NxNjMCAXFb7Z+IOxi+X3Q8xCnAwKvHwOuy6kyLEmlhWXJl7 iFGCg1lJhLeH91aKEG9KYmVValF+fFFpTmrxIUZpDhYlcV6v8NQEIYH0xJLU7NTUgtQimCwT B6dUA2P3ZhuRjPWfy9UDL9z26D014an2cSOOpjOvI+OntWtMrQ+p2SNpWPVj2QsVLiutoiXX qjN3Ws1XdrSZJ3J4XdK6yXb2ZReTAuYZTZC5uetgx6lJb+9tT352WbFr53kbN+6wxQrll3s3 a7MJVh1adddld+L01eIGKb61jSeeFpRGPJjxOOjbRSYlluKMREMt5qLiRAD0GJvFRAIAAA== X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Add a sysctl knob, '/proc/sys/vm/migrc_enable' to switch on/off migrc. Signed-off-by: Byungchul Park --- mm/migrate.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 46 insertions(+), 2 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index badef3d89c6c..c57536a0b2a6 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -59,6 +59,48 @@ #include "internal.h" =20 #ifdef CONFIG_MIGRC +static int sysctl_migrc_enable =3D 1; +#ifdef CONFIG_SYSCTL +static int sysctl_migrc_enable_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct ctl_table t; + int err; + int enabled =3D sysctl_migrc_enable; + + if (write && !capable(CAP_SYS_ADMIN)) + return -EPERM; + + t =3D *table; + t.data =3D &enabled; + err =3D proc_dointvec_minmax(&t, write, buffer, lenp, ppos); + if (err < 0) + return err; + if (write) + sysctl_migrc_enable =3D enabled; + return err; +} + +static struct ctl_table migrc_sysctls[] =3D { + { + .procname =3D "migrc_enable", + .data =3D NULL, /* filled in by handler */ + .maxlen =3D sizeof(int), + .mode =3D 0644, + .proc_handler =3D sysctl_migrc_enable_handler, + .extra1 =3D SYSCTL_ZERO, + .extra2 =3D SYSCTL_ONE, + }, + {} +}; + +static int __init migrc_sysctl_init(void) +{ + register_sysctl_init("vm", migrc_sysctls); + return 0; +} +late_initcall(migrc_sysctl_init); +#endif =20 /* * TODO: Yeah, it's a non-sense magic number. This simple value manages @@ -288,6 +330,7 @@ int migrc_pending_nr_in_zone(struct zone *z) =20 } #else +static const int sysctl_migrc_enable; static inline bool migrc_src_pending(struct folio *f) { return false; } static inline bool migrc_dst_pending(struct folio *f) { return false; } static inline bool migrc_is_full(int nid) { return true; } @@ -1878,8 +1921,9 @@ static int migrate_pages_batch(struct list_head *from= , new_page_t get_new_page, VM_WARN_ON_ONCE(mode !=3D MIGRATE_ASYNC && !list_empty(from) && !list_is_singular(from)); =20 - migrc_cond1 =3D (reason =3D=3D MR_DEMOTION && current_is_kswapd()) || - (reason =3D=3D MR_NUMA_MISPLACED); + migrc_cond1 =3D sysctl_migrc_enable && + ((reason =3D=3D MR_DEMOTION && current_is_kswapd()) || + (reason =3D=3D MR_NUMA_MISPLACED)); =20 if (migrc_cond1) migrc_req_start(); --=20 2.17.1