From patchwork Mon Dec 6 03:16:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Ying" X-Patchwork-Id: 12657637 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44917C433EF for ; Mon, 6 Dec 2021 03:17:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9EDFC6B007B; Sun, 5 Dec 2021 22:17:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 976196B007D; Sun, 5 Dec 2021 22:17:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7EF8C6B007E; Sun, 5 Dec 2021 22:17:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0206.hostedemail.com [216.40.44.206]) by kanga.kvack.org (Postfix) with ESMTP id 686E16B007B for ; Sun, 5 Dec 2021 22:17:30 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 247D68249980 for ; Mon, 6 Dec 2021 03:17:20 +0000 (UTC) X-FDA: 78885908640.07.0782BAE Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by imf09.hostedemail.com (Postfix) with ESMTP id 25A123000105 for ; Mon, 6 Dec 2021 03:17:22 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10189"; a="300624004" X-IronPort-AV: E=Sophos;i="5.87,290,1631602800"; d="scan'208";a="300624004" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Dec 2021 19:17:17 -0800 X-IronPort-AV: E=Sophos;i="5.87,290,1631602800"; d="scan'208";a="478972618" Received: from yhuang6-desk2.sh.intel.com ([10.239.159.50]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Dec 2021 19:17:15 -0800 From: Huang Ying To: Peter Zijlstra , Mel Gorman Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Mel Gorman , Greg Kroah-Hartman , Valentin Schneider , stable@vger.kernel.org Subject: [PATCH] numa balancing: remove some outdated document Date: Mon, 6 Dec 2021 11:16:45 +0800 Message-Id: <20211206031645.3412350-1-ying.huang@intel.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 25A123000105 X-Stat-Signature: c4xhr9g9aqzg3xk9gyqcwxtrkryp3b9t Authentication-Results: imf09.hostedemail.com; dkim=none; dmarc=fail reason="No valid SPF, No valid DKIM" header.from=intel.com (policy=none); spf=none (imf09.hostedemail.com: domain of ying.huang@intel.com has no SPF policy when checking 134.134.136.100) smtp.mailfrom=ying.huang@intel.com X-HE-Tag: 1638760642-982179 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: After commit 8a99b6833c88 ("sched: Move SCHED_DEBUG sysctl to debugfs"), some NUMA balancing sysctls enclosed with SCHED_DEBUG has been moved to debugfs. This patch removes the document for the sysctls to keep the document consistent with the code. Signed-off-by: "Huang, Ying" Fixes: 8a99b6833c88 ("sched: Move SCHED_DEBUG sysctl to debugfs") Cc: Mel Gorman Cc: Peter Zijlstra (Intel) Cc: Greg Kroah-Hartman Cc: Valentin Schneider Cc: stable@vger.kernel.org # since v5.13 --- Documentation/admin-guide/sysctl/kernel.rst | 46 +-------------------- 1 file changed, 1 insertion(+), 45 deletions(-) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 426162009ce9..d2679ea6936e 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -609,51 +609,7 @@ be migrated to a local memory node. The unmapping of pages and trapping faults incur additional overhead that ideally is offset by improved memory locality but there is no universal guarantee. If the target workload is already bound to NUMA nodes then this -feature should be disabled. Otherwise, if the system overhead from the -feature is too high then the rate the kernel samples for NUMA hinting -faults may be controlled by the `numa_balancing_scan_period_min_ms, -numa_balancing_scan_delay_ms, numa_balancing_scan_period_max_ms, -numa_balancing_scan_size_mb`_, and numa_balancing_settle_count sysctls. - - -numa_balancing_scan_period_min_ms, numa_balancing_scan_delay_ms, numa_balancing_scan_period_max_ms, numa_balancing_scan_size_mb -=============================================================================================================================== - - -Automatic NUMA balancing scans tasks address space and unmaps pages to -detect if pages are properly placed or if the data should be migrated to a -memory node local to where the task is running. Every "scan delay" the task -scans the next "scan size" number of pages in its address space. When the -end of the address space is reached the scanner restarts from the beginning. - -In combination, the "scan delay" and "scan size" determine the scan rate. -When "scan delay" decreases, the scan rate increases. The scan delay and -hence the scan rate of every task is adaptive and depends on historical -behaviour. If pages are properly placed then the scan delay increases, -otherwise the scan delay decreases. The "scan size" is not adaptive but -the higher the "scan size", the higher the scan rate. - -Higher scan rates incur higher system overhead as page faults must be -trapped and potentially data must be migrated. However, the higher the scan -rate, the more quickly a tasks memory is migrated to a local node if the -workload pattern changes and minimises performance impact due to remote -memory accesses. These sysctls control the thresholds for scan delays and -the number of pages scanned. - -``numa_balancing_scan_period_min_ms`` is the minimum time in milliseconds to -scan a tasks virtual memory. It effectively controls the maximum scanning -rate for each task. - -``numa_balancing_scan_delay_ms`` is the starting "scan delay" used for a task -when it initially forks. - -``numa_balancing_scan_period_max_ms`` is the maximum time in milliseconds to -scan a tasks virtual memory. It effectively controls the minimum scanning -rate for each task. - -``numa_balancing_scan_size_mb`` is how many megabytes worth of pages are -scanned for a given scan. - +feature should be disabled. oops_all_cpu_backtrace ======================