From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6797C4363C for ; Wed, 7 Oct 2020 18:05:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 61FD621707 for ; Wed, 7 Oct 2020 18:05:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="U8T7JcyS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728477AbgJGSFO (ORCPT ); Wed, 7 Oct 2020 14:05:14 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:36761 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727085AbgJGSFL (ORCPT ); Wed, 7 Oct 2020 14:05:11 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602093911; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc; bh=x/Tqa0d9nodar351Zfey/2sT9+zcJbqgkTtkMif06fY=; b=U8T7JcyS12Gu36NsdDkalVgRkjhirEskev6wOX5sDdRdhpZwXsquIkyAcw7fACaDcxblMp JUOLNK5SjVaSDaWQ6vbXR/zW0xv7zfC+hbNT7KlUY88/g68stPHIAIVetI2XwDYUDM6zO7 pQ/YcGRSejJxRB1DzYPn00ULueHb9ak= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-11-8wpLJ0giOneXwXnlY2T7eg-1; Wed, 07 Oct 2020 14:05:07 -0400 X-MC-Unique: 8wpLJ0giOneXwXnlY2T7eg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D5B17801AFA; Wed, 7 Oct 2020 18:05:02 +0000 (UTC) Received: from fuller.cnet (ovpn-112-4.gru2.redhat.com [10.97.112.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 44FC65D9F1; Wed, 7 Oct 2020 18:04:57 +0000 (UTC) Received: by fuller.cnet (Postfix, from userid 1000) id 657D2416948A; Wed, 7 Oct 2020 15:04:33 -0300 (-03) Message-ID: <20201007180151.623061463@redhat.com> User-Agent: quilt/0.66 Date: Wed, 07 Oct 2020 15:01:51 -0300 From: Marcelo Tosatti To: linux-kernel@vger.kernel.org Cc: Frederic Weisbecker , Peter Zijlstra , Nitesh Narayan Lal , Peter Xu Subject: [patch 0/2] nohz_full: only wakeup target CPUs when notifying new tick dependency (v2) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When enabling per-CPU posix timers, an IPI to nohz_full CPUs might be performed (to re-read the dependencies and possibly not re-enter nohz_full on a given CPU). A common case is for applications that run on nohz_full= CPUs to not use POSIX timers (eg DPDK). This patch changes the notification to only IPI the target CPUs where the task(s) whose tick dependencies are being updated are executing. This reduces interruptions to nohz_full= CPUs.