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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 2EE41C33CB1 for ; Thu, 16 Jan 2020 09:48:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F1FC120661 for ; Thu, 16 Jan 2020 09:48:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FICHmaE1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731638AbgAPJsg (ORCPT ); Thu, 16 Jan 2020 04:48:36 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:50719 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726827AbgAPJsf (ORCPT ); Thu, 16 Jan 2020 04:48:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579168114; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=jQUfRvThpvCpmExVhDXPSctOGTZhMUj3J1KVohZFS0U=; b=FICHmaE1tkP5fY72HeY8dDMrn7CzlPvIJxTW8+p6QQr8QoMjEzwgxywDUYbVuQDB6a+cJG RGxoHD7QbXVja1uJj/1i6Xz0HZeU1vky/rdMRscPtTC+hsE2ekRmqVpaeLniBGffYZEmwW adK6yeWwx2JldDsRfVytmsWXu4QuqrM= 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-323-fRAPxkJKN5KLUUn6k_w3xQ-1; Thu, 16 Jan 2020 04:48:32 -0500 X-MC-Unique: fRAPxkJKN5KLUUn6k_w3xQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 259D8107ACC5; Thu, 16 Jan 2020 09:48:31 +0000 (UTC) Received: from localhost (ovpn-8-20.pek2.redhat.com [10.72.8.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3955784333; Thu, 16 Jan 2020 09:48:22 +0000 (UTC) From: Ming Lei To: linux-kernel@vger.kernel.org Cc: Ming Lei , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Peter Xu , Juri Lelli Subject: [PATCH] sched/isolation: isolate from handling managed interrupt Date: Thu, 16 Jan 2020 17:48:06 +0800 Message-Id: <20200116094806.25372-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Userspace can't change managed interrupt's affinity via /proc interface, however application often requires the specified isolated CPUs not disturbed by interrupts. Add sub-parameter 'managed_irq' for 'isolcpus', so that we can isolate from handling managed interrupt. Not select isolated CPU as effective CPU if the interupt affinity include= s at least one housekeeping CPU. This way guarantees that isolated CPUs won= 't be interrupted by managed irq if IO isn't submitted from any isolated CPU= . Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Peter Xu Cc: Juri Lelli Signed-off-by: Ming Lei --- .../admin-guide/kernel-parameters.txt | 9 ++++++++ include/linux/sched/isolation.h | 1 + kernel/irq/manage.c | 22 ++++++++++++++++++- kernel/sched/isolation.c | 6 +++++ 4 files changed, 37 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentat= ion/admin-guide/kernel-parameters.txt index ade4e6ec23e0..e0f18ac866d4 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1933,6 +1933,15 @@ begins at 0 and the maximum value is "number of CPUs in system - 1". =20 + managed_irq + Isolate from handling managed interrupt. Userspace can't + change managed interrupt's affinity via /proc interface, + however application often requires the specified isolated + CPUs not disturbed by interrupts. This way guarantees that + isolated CPU won't be interrupted if IO isn't submitted + from isolated CPU when managed interrupt is used by IO + drivers. + The format of is described above. =20 =20 diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolat= ion.h index 6c8512d3be88..0fbcbacd1b29 100644 --- a/include/linux/sched/isolation.h +++ b/include/linux/sched/isolation.h @@ -13,6 +13,7 @@ enum hk_flags { HK_FLAG_TICK =3D (1 << 4), HK_FLAG_DOMAIN =3D (1 << 5), HK_FLAG_WQ =3D (1 << 6), + HK_FLAG_MANAGED_IRQ =3D (1 << 7), }; =20 #ifdef CONFIG_CPU_ISOLATION diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 1753486b440c..9cc972d28d3c 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -20,6 +20,7 @@ #include #include #include +#include =20 #include "internals.h" =20 @@ -212,12 +213,29 @@ int irq_do_set_affinity(struct irq_data *data, cons= t struct cpumask *mask, { struct irq_desc *desc =3D irq_data_to_desc(data); struct irq_chip *chip =3D irq_data_get_irq_chip(data); + const struct cpumask *housekeeping_mask =3D + housekeeping_cpumask(HK_FLAG_MANAGED_IRQ); int ret; + cpumask_var_t tmp_mask =3D (struct cpumask *)mask; =20 if (!chip || !chip->irq_set_affinity) return -EINVAL; =20 - ret =3D chip->irq_set_affinity(data, mask, force); + zalloc_cpumask_var(&tmp_mask, GFP_ATOMIC); + + /* + * Userspace can't change managed irq's affinity, make sure that + * isolated CPU won't be selected as the effective CPU if this + * irq's affinity includes at least one housekeeping CPU. + * + * This way guarantees that isolated CPU won't be interrupted if + * IO isn't submitted from isolated CPU. + */ + if (irqd_affinity_is_managed(data) && tmp_mask && + cpumask_intersects(mask, housekeeping_mask)) + cpumask_and(tmp_mask, mask, housekeeping_mask); + + ret =3D chip->irq_set_affinity(data, tmp_mask, force); switch (ret) { case IRQ_SET_MASK_OK: case IRQ_SET_MASK_OK_DONE: @@ -229,6 +247,8 @@ int irq_do_set_affinity(struct irq_data *data, const = struct cpumask *mask, ret =3D 0; } =20 + free_cpumask_var(tmp_mask); + return ret; } =20 diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 9fcb2a695a41..008d6ac2342b 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -163,6 +163,12 @@ static int __init housekeeping_isolcpus_setup(char *= str) continue; } =20 + if (!strncmp(str, "managed_irq,", 12)) { + str +=3D 12; + flags |=3D HK_FLAG_MANAGED_IRQ; + continue; + } + pr_warn("isolcpus: Error, unknown flag\n"); return 0; } --=20 2.20.1