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Wed, 24 Jun 2020 04:13:35 -0400 Received: from mail-qk1-x72d.google.com (mail-qk1-x72d.google.com [IPv6:2607:f8b0:4864:20::72d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D7EBC061573 for ; Wed, 24 Jun 2020 01:13:35 -0700 (PDT) Received: by mail-qk1-x72d.google.com with SMTP id l6so1070228qkc.6 for ; Wed, 24 Jun 2020 01:13:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=from:references:in-reply-to:mime-version:thread-index:date :message-id:subject:to:cc:content-transfer-encoding; bh=YiwAw5rf1diC6i54PRBuyM8/xbCVl7h6LSmw94lDr8M=; b=DLNnplMZTclq3Qu41yzxfjHqZxOrk1DU+y+luEo+7KmlVHvLHuvdtKEvab9Yn8iIf9 h7k2rv2GRt+e0qBArwvSGj9sTnX37oqP7KFHi1MJAFHqrF3q7NMt62BE+LPptI0PU3yz 47Gd6tdJZ/LyEtctL/O7p0BQ/cqnmm4TQB1Xs= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:references:in-reply-to:mime-version :thread-index:date:message-id:subject:to:cc :content-transfer-encoding; bh=YiwAw5rf1diC6i54PRBuyM8/xbCVl7h6LSmw94lDr8M=; 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charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org > > On 6/23/20 1:25 PM, John Garry wrote: > > On 11/06/2020 09:26, John Garry wrote: > >> On 11/06/2020 03:57, Ming Lei wrote: > >>> On Thu, Jun 11, 2020 at 01:29:09AM +0800, John Garry wrote: > >>>> From: Hannes Reinecke > >>>> > >>>> The function does not set the depth, but rather transitions from > >>>> shared to non-shared queues and vice versa. > >>>> So rename it to blk_mq_update_tag_set_shared() to better reflect > >>>> its purpose. > >>> > >>> It is fine to rename it for me, however: > >>> > >>> This patch claims to rename blk_mq_update_tag_set_shared(), but also > >>> change blk_mq_init_bitmap_tags's signature. > >> > >> I was going to update the commit message here, but forgot again... > >> > >>> > >>> So suggest to split this patch into two or add comment log on > >>> changing blk_mq_init_bitmap_tags(). > >> > >> I think I'll just split into 2x commits. > > > > Hi Hannes, > > > > Do you have any issue with splitting the undocumented changes into > > another patch as so: > > > No, that's perfectly fine. > > Kashyap, I've also attached an updated patch for the elevator_count patch= ; > if > you agree John can include it in the next version. Hannes - Patch looks good. Header does not include problem statement. How about adding below in header ? High CPU utilization on "native_queued_spin_lock_slowpath" due to lock contention is possible in mq-deadline and bfq io scheduler when nr_hw_queue= s is more than one. It is because kblockd work queue can submit IO from all online CPUs (throug= h blk_mq_run_hw_queues) even though only one hctx has pending commands. Elevator callback "has_work" for mq-deadline and bfq scheduler consider pending work if there are any IOs on request queue and it does not account hctx context. I have not seen performance drop after this patch, but I will continue further testing. John - One more thing, I am working on megaraid_sas driver to provide both host_tagset =3D 1 and 0 option through module parameter. Kashyap > > Cheers, > > Hannes > -- > Dr. Hannes Reinecke Teamlead Storage & Networking > hare@suse.de +49 911 74053 688 > SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg HRB 3680= 9 > (AG N=C3=BCrnberg), Gesch=C3=A4ftsf=C3=BChrer: Felix Imend=C3=B6rffer