From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754698AbdECSps (ORCPT ); Wed, 3 May 2017 14:45:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38822 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753616AbdECSpE (ORCPT ); Wed, 3 May 2017 14:45:04 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 278B77F3F8 Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=mtosatti@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 278B77F3F8 Message-Id: <20170503184007.174707977@redhat.com> User-Agent: quilt/0.60-1 Date: Wed, 03 May 2017 15:40:07 -0300 From: Marcelo Tosatti To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Luiz Capitulino , Rik van Riel , Linux RT Users Subject: [patch 0/3] per-CPU vmstat thresholds and vmstat worker disablement (v2) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 03 May 2017 18:45:04 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The per-CPU vmstat worker is a problem on -RT workloads (because ideally the CPU is entirely reserved for the -RT app, without interference). The worker transfers accumulated per-CPU vmstat counters to global counters. To resolve the problem, create two tunables: * Userspace configurable per-CPU vmstat threshold: by default the VM code calculates the size of the per-CPU vmstat arrays. This tunable allows userspace to configure the values. * Userspace configurable per-CPU vmstat worker: allow disabling the per-CPU vmstat worker. v2: - Improve documentation (Rik/Luiz). - Split patch in two (Luiz). - Fix comparison to include equal, in the helpers for stats accounting.