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 9E75BC433EF for ; Tue, 5 Oct 2021 12:37:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83C1960EFD for ; Tue, 5 Oct 2021 12:37:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234461AbhJEMiH (ORCPT ); Tue, 5 Oct 2021 08:38:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234459AbhJEMhq (ORCPT ); Tue, 5 Oct 2021 08:37:46 -0400 Received: from mail-io1-xd35.google.com (mail-io1-xd35.google.com [IPv6:2607:f8b0:4864:20::d35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32A9EC06174E for ; Tue, 5 Oct 2021 05:35:55 -0700 (PDT) Received: by mail-io1-xd35.google.com with SMTP id e144so24109007iof.3 for ; Tue, 05 Oct 2021 05:35:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=nd2ejrVn1IrBzoTnNUOEIyw1dA744hB3m7HTfczVCYw=; b=xmvqwh+kxSPa9x9HeEtsBRyEMZbiwmF9kmT2OvILc5pg90cUkpuaMZ5OvHxKqkDYU/ 1fpVksM05Rf0fxzEAil/CPpgNnKkpCNejmW21owoiE3aWLED7++R8k81uvojfVvqc7ci HHXXOXOa9lBEMqLOMKVKNocxqsF+0fQcu+AQ08kIFpjn5xBRAdKSlfOYM9Apu+9R1+eY SHsfuYhDY6L8gqWWZaKmVr3FcM7xqLEmeo/ExEEu7PQfnMv9yRp+FF0GUJngHr9mvWDX kTsCNcRsjwP+pp6QAXebSf40N/OR4D2lHP2fsAz5ikvIPfnSdkdPZWCCpOhP/G2e1N4n RT+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=nd2ejrVn1IrBzoTnNUOEIyw1dA744hB3m7HTfczVCYw=; b=q7GsLbx59aFaR0cMUyb89gx7xeHBvb2rviQPBdOO0E83s4xSPxV/W7HRnd8edoPohe tOHrqHZMfmqtw88kceBFZsHqfN0k1HDhMy1lyMZoqwzAZqE7pqe+eTsKueU6B/tfcAEd ulLUmtXFm1OvKpEyu2KjuyYOpYQssSyEOoQohq89cNyJ4ZSxDBZQvdFO9oDnyC6x+RSH ZTSrMRK8RNMAQElEd6K5KknMQm7bQgbDZ2UmyumwoAXMhxyUbtaH41/D/oJIYKoM34zz RhRmNnX6B/B60vALiWnPGH+xHgXRCZmRpon0Kz/Z9rXqlmbtLce2yfPzodbgZncRMkHh xqeA== X-Gm-Message-State: AOAM530VHYkM539EDDBjTdctTKYB3KkMHbTS60vrU0hADvwS85lT48YB f00od6O3LY6t7edDWqhgT6/oDA== X-Google-Smtp-Source: ABdhPJwRiZXSHS0qUfot1WPJLc5czmuF+55CPQgpqu62Bytbnh3tfhH63y5zGznVaUNcr7o0Yrnpfg== X-Received: by 2002:a02:7006:: with SMTP id f6mr136991jac.113.1633437354591; Tue, 05 Oct 2021 05:35:54 -0700 (PDT) Received: from [192.168.1.116] ([66.219.217.159]) by smtp.gmail.com with ESMTPSA id a4sm8961525ild.52.2021.10.05.05.35.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 05 Oct 2021 05:35:54 -0700 (PDT) Subject: Re: [PATCH v5 00/14] blk-mq: Reduce static requests memory footprint for shared sbitmap To: John Garry Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ming.lei@redhat.com, hare@suse.de, linux-scsi@vger.kernel.org, kashyap.desai@broadcom.com References: <1633429419-228500-1-git-send-email-john.garry@huawei.com> From: Jens Axboe Message-ID: Date: Tue, 5 Oct 2021 06:35:52 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1633429419-228500-1-git-send-email-john.garry@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 10/5/21 4:23 AM, John Garry wrote: > Currently a full set of static requests are allocated per hw queue per > tagset when shared sbitmap is used. > > However, only tagset->queue_depth number of requests may be active at > any given time. As such, only tagset->queue_depth number of static > requests are required. > > The same goes for using an IO scheduler, which allocates a full set of > static requests per hw queue per request queue. > > This series changes shared sbitmap support by using a shared tags per > tagset and request queue. Ming suggested something along those lines in > v1 review. In using a shared tags, the static rqs also become shared, > reducing the number of sets of static rqs, reducing memory usage. > > Patch "blk-mq: Use shared tags for shared sbitmap support" is a bit big, > and could potentially be broken down. But then maintaining ability to > bisect becomes harder and each sub-patch would get more convoluted. > > For megaraid sas driver on my 128-CPU arm64 system with 1x SATA disk, we > save approx. 300MB(!) [370MB -> 60MB] > > Baseline is 1b2d1439fc25 (block/for-next) Merge branch 'for-5.16/io_uring' > into for-next Let's get this queued up for testing, thanks John. -- Jens Axboe