From patchwork Mon Nov 15 23:33:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 517431 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E901C433FE for ; Mon, 15 Nov 2021 23:38:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4566061AFF for ; Mon, 15 Nov 2021 23:38:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355376AbhKOXlG (ORCPT ); Mon, 15 Nov 2021 18:41:06 -0500 Received: from mail.kernel.org ([198.145.29.99]:45360 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355081AbhKOXjA (ORCPT ); Mon, 15 Nov 2021 18:39:00 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B375661A0C; Mon, 15 Nov 2021 23:34:03 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.95) (envelope-from ) id 1mmlUA-000ou3-Qz; Mon, 15 Nov 2021 18:34:02 -0500 Message-ID: <20211115233402.665115219@goodmis.org> User-Agent: quilt/0.66 Date: Mon, 15 Nov 2021 18:33:44 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Daniel Wagner , Tom Zanussi , "Srivatsa S. Bhat" , stable-rt@vger.kernel.org, Mel Gorman Subject: [PATCH RT 5/9] mm: Disable NUMA_BALANCING_DEFAULT_ENABLED and TRANSPARENT_HUGEPAGE on PREEMPT_RT References: <20211115233339.509057092@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org 5.10.78-rt56-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior TRANSPARENT_HUGEPAGE: There are potential non-deterministic delays to an RT thread if a critical memory region is not THP-aligned and a non-RT buffer is located in the same hugepage-aligned region. It's also possible for an unrelated thread to migrate pages belonging to an RT task incurring unexpected page faults due to memory defragmentation even if khugepaged is disabled. Regular HUGEPAGEs are not affected by this can be used. NUMA_BALANCING: There is a non-deterministic delay to mark PTEs PROT_NONE to gather NUMA fault samples, increased page faults of regions even if mlocked and non-deterministic delays when migrating pages. [Mel Gorman worded 99% of the commit description]. Link: https://lore.kernel.org/all/20200304091159.GN3818@techsingularity.net/ Link: https://lore.kernel.org/all/20211026165100.ahz5bkx44lrrw5pt@linutronix.de/ Cc: stable-rt@vger.kernel.org Cc: Mel Gorman Signed-off-by: Sebastian Andrzej Siewior Acked-by: Mel Gorman Link: https://lore.kernel.org/r/20211028143327.hfbxjze7palrpfgp@linutronix.de Signed-off-by: Steven Rostedt (VMware) --- init/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index 7ba2b602b707..9bfc60e7eead 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -861,7 +861,7 @@ config NUMA_BALANCING bool "Memory placement aware NUMA scheduler" depends on ARCH_SUPPORTS_NUMA_BALANCING depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY - depends on SMP && NUMA && MIGRATION + depends on SMP && NUMA && MIGRATION && !PREEMPT_RT help This option adds support for automatic NUMA aware memory/task placement. The mechanism is quite primitive and is based on migrating memory when