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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBBD0C433EF for ; Tue, 2 Nov 2021 13:57:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1ECA60EDF for ; Tue, 2 Nov 2021 13:57:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231161AbhKBOAX (ORCPT ); Tue, 2 Nov 2021 10:00:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49658 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231348AbhKBOAX (ORCPT ); Tue, 2 Nov 2021 10:00:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1635861467; 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=I1z5tRr3ZGJF45UtoRAB1ZvSOjDWZRiUGmxZduFxiFI=; b=LVDaIqH36GlA79w3vXiJQVdtP1sFpbjOTz4YsyQR8aTXOs/s3g9SGo7rSzEaxsons570g/ oJioMbeCWUWOhP2COUb1KfkddSnfsUmyK/7kIWl0KzessA8MdtTCLcpvcTWn6RlShm84l8 kV+ab1Ig+dR/c+1elkEDQ3+U4GIJh4o= 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-510-AmgyrCzsMWCn48DRo-cf8w-1; Tue, 02 Nov 2021 09:57:43 -0400 X-MC-Unique: AmgyrCzsMWCn48DRo-cf8w-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 EC05456C9C; Tue, 2 Nov 2021 13:57:42 +0000 (UTC) Received: from T590 (ovpn-8-19.pek2.redhat.com [10.72.8.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4BB8B26E40; Tue, 2 Nov 2021 13:57:39 +0000 (UTC) Date: Tue, 2 Nov 2021 21:57:35 +0800 From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Shinichiro Kawasaki , ming.lei@redhat.com Subject: Re: [PATCH 3/3] blk-mq: update hctx->nr_active in blk_mq_end_request_batch() Message-ID: References: <20211102133502.3619184-1-ming.lei@redhat.com> <20211102133502.3619184-4-ming.lei@redhat.com> <922449db-73a7-efaf-52ef-d386edf77953@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <922449db-73a7-efaf-52ef-d386edf77953@kernel.dk> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Nov 02, 2021 at 07:47:44AM -0600, Jens Axboe wrote: > On 11/2/21 7:35 AM, Ming Lei wrote: > > In case of shared tags and none io sched, batched completion still may > > be run into, and hctx->nr_active is accounted when getting driver tag, > > so it has to be updated in blk_mq_end_request_batch(). > > > > Otherwise, hctx->nr_active may become same with queue depth, then > > hctx_may_queue() always return false, then io hang is caused. > > > > Fixes the issue by updating the counter in batched way. > > > > Reported-by: Shinichiro Kawasaki > > Fixes: f794f3351f26 ("block: add support for blk_mq_end_request_batch()") > > Signed-off-by: Ming Lei > > --- > > block/blk-mq.c | 15 +++++++++++++-- > > block/blk-mq.h | 12 +++++++++--- > > 2 files changed, 22 insertions(+), 5 deletions(-) > > > > diff --git a/block/blk-mq.c b/block/blk-mq.c > > index 07eb1412760b..0dbe75034f61 100644 > > --- a/block/blk-mq.c > > +++ b/block/blk-mq.c > > @@ -825,6 +825,7 @@ void blk_mq_end_request_batch(struct io_comp_batch *iob) > > struct blk_mq_hw_ctx *cur_hctx = NULL; > > struct request *rq; > > u64 now = 0; > > + int active = 0; > > > > if (iob->need_ts) > > now = ktime_get_ns(); > > @@ -846,16 +847,26 @@ void blk_mq_end_request_batch(struct io_comp_batch *iob) > > rq_qos_done(rq->q, rq); > > > > if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) { > > - if (cur_hctx) > > + if (cur_hctx) { > > + if (active) > > + __blk_mq_sub_active_requests(cur_hctx, > > + active); > > blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags); > > + } > > nr_tags = 0; > > + active = 0; > > cur_hctx = rq->mq_hctx; > > } > > tags[nr_tags++] = rq->tag; > > + if (rq->rq_flags & RQF_MQ_INFLIGHT) > > + active++; > > Are there any cases where either none or all of requests have the flag set, and > hence active == nr_tags? none and BLK_MQ_F_TAG_QUEUE_SHARED, and Shinichiro only observed the issue on two NSs. Thanks, Ming