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=-5.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 AE709C3A5A9 for ; Tue, 5 May 2020 02:09:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88534206D7 for ; Tue, 5 May 2020 02:09:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="S/YV2G0B" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726635AbgEECJu (ORCPT ); Mon, 4 May 2020 22:09:50 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:40406 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726551AbgEECJt (ORCPT ); Mon, 4 May 2020 22:09:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588644587; 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=WYnkD58WxeGhOck7Zlrajuf0o20cMqrAWncxJYevXaA=; b=S/YV2G0BID44AYG/hOHKXZtPTtYiqls6ib3wuHGzd6q7c5hTu9Yvv1MBqDqm7E1Mu4nM84 iLck7DkupDrt2X8kvTjs7afYxZ7DdlxKwefUEXhs9Sf3v9m2SbAsMKEHnunWrqKF/0n6IJ Rt8k59Cy+vdMHpmAShIKxjen3QnQK28= 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-281-Arvhap67Nwik-fcXhmYa-g-1; Mon, 04 May 2020 22:09:44 -0400 X-MC-Unique: Arvhap67Nwik-fcXhmYa-g-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 89CBE1800D4A; Tue, 5 May 2020 02:09:42 +0000 (UTC) Received: from localhost (ovpn-8-17.pek2.redhat.com [10.72.8.17]) by smtp.corp.redhat.com (Postfix) with ESMTP id AC4DF62490; Tue, 5 May 2020 02:09:37 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Ming Lei , John Garry , Bart Van Assche , Hannes Reinecke , Christoph Hellwig , Thomas Gleixner Subject: [PATCH V10 00/11] blk-mq: improvement CPU hotplug Date: Tue, 5 May 2020 10:09:19 +0800 Message-Id: <20200505020930.1146281-1-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-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi, Thomas mentioned: " That was the constraint of managed interrupts from the very beginnin= g: =20 The driver/subsystem has to quiesce the interrupt line and the asso= ciated queue _before_ it gets shutdown in CPU unplug and not fiddle with i= t until it's restarted by the core when the CPU is plugged in again. " But no drivers or blk-mq do that before one hctx becomes inactive(all CPUs for one hctx are offline), and even it is worse, blk-mq stills tries to run hw queue after hctx is dead, see blk_mq_hctx_notify_dead(). This patchset tries to address the issue by two stages: 1) add one new cpuhp state of CPUHP_AP_BLK_MQ_ONLINE - mark the hctx as internal stopped, and drain all in-flight requests if the hctx is going to be dead. 2) re-submit IO in the state of CPUHP_BLK_MQ_DEAD after the hctx becomes = dead - steal bios from the request, and resubmit them via generic_make_request= (), then these IO will be mapped to other live hctx for dispatch Thanks John Garry for running lots of tests on arm64 with this patchset and co-working on investigating all kinds of issues. Thanks Christoph's review on V7 & V8. Please comment & review, thanks! https://github.com/ming1/linux/commits/v5.7-rc-blk-mq-improve-cpu-hotplug V10: - fix double bio complete in request resubmission(10/11) - add tested-by tag V9: - add Reviewed-by tag - document more on memory barrier usage between getting driver tag and handling cpu offline(7/11) - small code cleanup as suggested by Chritoph(7/11) - rebase against for-5.8/block(1/11, 2/11) V8: - add patches to share code with blk_rq_prep_clone - code re-organization as suggested by Christoph, most of them are in 04/11, 10/11 - add reviewed-by tag V7: - fix updating .nr_active in get_driver_tag - add hctx->cpumask check in cpuhp handler - only drain requests which tag is >=3D 0 - pass more aggressive cpuhotplug&io test V6: - simplify getting driver tag, so that we can drain in-flight requests correctly without using synchronize_rcu() - handle re-submission of flush & passthrough request correctly V5: - rename BLK_MQ_S_INTERNAL_STOPPED as BLK_MQ_S_INACTIVE - re-factor code for re-submit requests in cpu dead hotplug handler - address requeue corner case V4: - resubmit IOs in dispatch list in case that this hctx is dead=20 V3: - re-organize patch 2 & 3 a bit for addressing Hannes's comment - fix patch 4 for avoiding potential deadlock, as found by Hannes V2: - patch4 & patch 5 in V1 have been merged to block tree, so remove them - address comments from John Garry and Minwoo Ming Lei (11): block: clone nr_integrity_segments and write_hint in blk_rq_prep_clone block: add helper for copying request blk-mq: mark blk_mq_get_driver_tag as static blk-mq: assign rq->tag in blk_mq_get_driver_tag blk-mq: support rq filter callback when iterating rqs blk-mq: prepare for draining IO when hctx's all CPUs are offline blk-mq: stop to handle IO and drain IO before hctx becomes inactive block: add blk_end_flush_machinery blk-mq: add blk_mq_hctx_handle_dead_cpu for handling cpu dead blk-mq: re-submit IO in case that hctx is inactive block: deactivate hctx when the hctx is actually inactive block/blk-core.c | 27 ++- block/blk-flush.c | 141 ++++++++++++--- block/blk-mq-debugfs.c | 2 + block/blk-mq-tag.c | 39 ++-- block/blk-mq-tag.h | 4 + block/blk-mq.c | 356 +++++++++++++++++++++++++++++-------- block/blk-mq.h | 22 ++- block/blk.h | 11 +- drivers/block/loop.c | 2 +- drivers/md/dm-rq.c | 2 +- include/linux/blk-mq.h | 6 + include/linux/cpuhotplug.h | 1 + 12 files changed, 481 insertions(+), 132 deletions(-) Cc: John Garry Cc: Bart Van Assche Cc: Hannes Reinecke Cc: Christoph Hellwig Cc: Thomas Gleixner --=20 2.25.2