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=-5.8 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 BD10FC38A2A for ; Fri, 8 May 2020 21:50:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9932C21655 for ; Fri, 8 May 2020 21:50:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="eKTDYIBe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728058AbgEHVuF (ORCPT ); Fri, 8 May 2020 17:50:05 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:42155 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726811AbgEHVuF (ORCPT ); Fri, 8 May 2020 17:50:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588974603; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=S7rsKhPQ76I9sc+0hqYQCZZQoCeQHSBJEn+RrCufunc=; b=eKTDYIBeMAiV4oPJaaNwG3lNSm+aFSx+WBYGQBjOrgNwwqbnjVYawJptxhlS6xFZZN/wn2 X7ikrBJb/ZUF5orjbKfAMQyCNl9jO8gD19RaZYKrApmIX2cA03CPx6BbiP9YFxVC6rf2jO 9ltrsCepmH0Q//pSyVO7/XVdAvIyOOI= 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-455-gm75jjHjNt-UozZmeCqZ3w-1; Fri, 08 May 2020 17:50:00 -0400 X-MC-Unique: gm75jjHjNt-UozZmeCqZ3w-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 473DB835B40; Fri, 8 May 2020 21:49:59 +0000 (UTC) Received: from T590 (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7099825262; Fri, 8 May 2020 21:49:51 +0000 (UTC) Date: Sat, 9 May 2020 05:49:46 +0800 From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, John Garry , Bart Van Assche , Hannes Reinecke , Christoph Hellwig , Thomas Gleixner Subject: Re: [PATCH V10 00/11] blk-mq: improvement CPU hotplug Message-ID: <20200508214946.GB1389136@T590> References: <20200505020930.1146281-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200505020930.1146281-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, May 05, 2020 at 10:09:19AM +0800, Ming Lei wrote: > Hi, > > Thomas mentioned: > " > That was the constraint of managed interrupts from the very beginning: > > The driver/subsystem has to quiesce the interrupt line and the associated > queue _before_ it gets shutdown in CPU unplug and not fiddle with it > 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 >= 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 > > 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 Hi Jens, This patches have been worked and discussed for a while, so any chance to make it in 5.8 if no any further comments? Thanks, Ming