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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC102C04A6A for ; Thu, 10 Aug 2023 19:24:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232869AbjHJTYt (ORCPT ); Thu, 10 Aug 2023 15:24:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236344AbjHJTYs (ORCPT ); Thu, 10 Aug 2023 15:24:48 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34588272C for ; Thu, 10 Aug 2023 12:23:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691695435; 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=eNpUhxfG0oagA+OSHR3CBYIVBwq8hSKrFiUJQDT85NI=; b=a5C3fAnJillqqDzf9asR/dEcy1BHnCTsbNR3l8JqIohN80KAuZbOM08fcl5sKOfJ6nwQ+B cGEqAUNmS42uRAdgcu2BCwJxJKPSh8W87nqlMm329I2Cucs6qZyouwspilCaED6edzzuDU vxqesVNudAiZBnogVVknCvWG9s67y90= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-204-PMjH__-IP6qTzF6xHAJQPg-1; Thu, 10 Aug 2023 15:23:54 -0400 X-MC-Unique: PMjH__-IP6qTzF6xHAJQPg-1 Received: by mail-wr1-f71.google.com with SMTP id ffacd0b85a97d-317dff409dfso537634f8f.1 for ; Thu, 10 Aug 2023 12:23:54 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691695433; x=1692300233; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=eNpUhxfG0oagA+OSHR3CBYIVBwq8hSKrFiUJQDT85NI=; b=VbxZy1TP4CxYSLNHePKCt9UAybKa/zI0Qa6kdKbE2eR5iJ7p3hX7o0he943sDdp6jx qXZEU1sEUMRUtxUxUkFDl52bwBsNm4lwJL4JW1W4PBVGez6XD8tbxZCCYQ+fHRbamTpG XxBSzHUB1Y9kXyiR6HTlOsyOfRjB4gvmj+A3tSdr3gEqz3VNexvQ5BuOV+fTVMYH5O0J 0t+V8zeydW73mZHEpky8nYPS84QDmJI2n/adQmE7N7cNdYsPmRLXBHMRh1OaXO2NDgbo eHw7e75OEBUAuiqKS5k8PXORbZKS0mc8wJG338Kw1uuk+U8wnoTepaOfiLtbnxAmH38J Fm1g== X-Gm-Message-State: AOJu0Yy7bA4qSWWNYEbVjc/4voTI8/vZacEeYu+/8Wzd1vG5ndbqAPq+ 7drYi09AFAQTSn5T0iIEURmkUYAS+eyCKWGEJr0MqD1AEEwwMUQ2pl2o66lWmHA11F+rTFVmMBj Qhiqn9QaGS0zlqP5btSVrc4g= X-Received: by 2002:a5d:444d:0:b0:317:ce01:fe99 with SMTP id x13-20020a5d444d000000b00317ce01fe99mr2842382wrr.9.1691695433189; Thu, 10 Aug 2023 12:23:53 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHR0CV1UmR4DNEMAn9v2ToSkc3HIbFYdNRmAuQjKcn2GH2b+kNRcs5y/tG7/rWE1x5qPYNz9w== X-Received: by 2002:a5d:444d:0:b0:317:ce01:fe99 with SMTP id x13-20020a5d444d000000b00317ce01fe99mr2842373wrr.9.1691695432826; Thu, 10 Aug 2023 12:23:52 -0700 (PDT) Received: from redhat.com ([2.55.27.97]) by smtp.gmail.com with ESMTPSA id h6-20020a5d6886000000b00317f01fa3c4sm3018221wru.112.2023.08.10.12.23.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Aug 2023 12:23:52 -0700 (PDT) Date: Thu, 10 Aug 2023 15:23:48 -0400 From: "Michael S. Tsirkin" To: Ming Lei Cc: Jens Axboe , Christoph Hellwig , linux-nvme@lists.infradead.org, "Martin K . Petersen" , linux-scsi@vger.kernel.org, linux-block@vger.kernel.org, Wen Xiong , Keith Busch , Jason Wang , virtualization@lists.linux-foundation.org Subject: Re: [PATCH V3 04/14] virtio-blk: limit max allowed submit queues Message-ID: <20230810152310-mutt-send-email-mst@kernel.org> References: <20230808104239.146085-1-ming.lei@redhat.com> <20230808104239.146085-5-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230808104239.146085-5-ming.lei@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Aug 08, 2023 at 06:42:29PM +0800, Ming Lei wrote: > Take blk-mq's knowledge into account for calculating io queues. > > Fix wrong queue mapping in case of kdump kernel. > > On arm and ppc64, 'maxcpus=1' is passed to kdump command line, see > `Documentation/admin-guide/kdump/kdump.rst`, so num_possible_cpus() > still returns all CPUs because 'maxcpus=1' just bring up one single > cpu core during booting. > > blk-mq sees single queue in kdump kernel, and in driver's viewpoint > there are still multiple queues, this inconsistency causes driver to apply > wrong queue mapping for handling IO, and IO timeout is triggered. > > Meantime, single queue makes much less resource utilization, and reduce > risk of kernel failure. > > Cc: Michael S. Tsirkin > Cc: Jason Wang > Cc: virtualization@lists.linux-foundation.org > Signed-off-by: Ming Lei superficially: Acked-by: Michael S. Tsirkin but this patch only makes sense if the rest of patchset is merged. feel free to merge directly. > --- > drivers/block/virtio_blk.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c > index 1fe011676d07..4ba79fe2a1b4 100644 > --- a/drivers/block/virtio_blk.c > +++ b/drivers/block/virtio_blk.c > @@ -1047,7 +1047,8 @@ static int init_vq(struct virtio_blk *vblk) > > num_poll_vqs = min_t(unsigned int, poll_queues, num_vqs - 1); > > - vblk->io_queues[HCTX_TYPE_DEFAULT] = num_vqs - num_poll_vqs; > + vblk->io_queues[HCTX_TYPE_DEFAULT] = min_t(unsigned, > + num_vqs - num_poll_vqs, blk_mq_max_nr_hw_queues()); > vblk->io_queues[HCTX_TYPE_READ] = 0; > vblk->io_queues[HCTX_TYPE_POLL] = num_poll_vqs; > > -- > 2.40.1