Received: by 2002:a25:ab43:0:0:0:0:0 with SMTP id u61csp3861394ybi; Mon, 3 Jun 2019 01:18:16 -0700 (PDT) X-Google-Smtp-Source: APXvYqx7EqKqNijl8DsK0ZtTw7QGRGiziCTDIY5P7Znu7ChQaWeR92wADmvPJUuB1vIJsgSBrRBX X-Received: by 2002:a62:1a0f:: with SMTP id a15mr30361647pfa.111.1559549896394; Mon, 03 Jun 2019 01:18:16 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1559549896; cv=none; d=google.com; s=arc-20160816; b=Hg6cOZEUc4I6g7YCQ8CeUy9R3uEtyuruLBvgwaqeFFjm1AV0JToaDKO4XklFeYbqwt pysSSlQeIE8LlUyb1/CqG2wyCt6qO4KGZpkZkskYhuSldIl+OooKQDNcd+6qIP+ng4gO 4qrFfTYz6Jxf+ZFVerdQgOgvM3eHSYzXmpyWv6hrBhqZWDGBFy01NZQ3ZmAfmfWctTu7 zTd5ngSWeKIcYw0d4Pgt5EYbhvEpe1NWZUGJl7ULSE23JGcCnCNVzUXsx3bZXTRDQtdY 3KEBGYaHnZMNPnX/Y5LIjD050gMZoqpMVEuT8cRru1zoPPj3/rM2RHYjV+mHimx/DTip rywQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding :content-language:in-reply-to:mime-version:user-agent:date :message-id:autocrypt:openpgp:from:references:cc:to:subject :dkim-signature; bh=4bw+bduVoO24yS9/ugPSh679fDtpvt1k54ZmtZYvvDY=; b=hXrXD64BVZk9/UtCB6giqDzfEIsR0m2jalFlIc+73WT4C1O/9fKE3Au6PxJ0vfTOuy 5O2nln4eNWZu6deRWobQbMsqp9Fkb0na5PfPMrWo0MPchLIbIM5ubIXsyW432AnidjmA 1W3PvSjnMQOxi4QuXgpFvc9Hz+SoF88p139Mj4gbblW8n8AhxiAsWE2NL9yMGQE/vNz6 LJrKHk6ghg237mVB++OSz0yRoY8qiDWiNTb8URkFrn2/ASCm8S9a3ZZiKXW5skUDSG8j g7BgVHNMtYsVRafwRqtTFjDI7NcVWn9Qqy1wsegJVu4ccE8/k0SglYEz3FhoftgxW1mS MgYw== ARC-Authentication-Results: i=1; mx.google.com; dkim=fail header.i=@gmail.com header.s=20161025 header.b="dDN/25Of"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id m8si16668589pgt.140.2019.06.03.01.17.59; Mon, 03 Jun 2019 01:18:16 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=fail header.i=@gmail.com header.s=20161025 header.b="dDN/25Of"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727669AbfFCIQ1 (ORCPT + 99 others); Mon, 3 Jun 2019 04:16:27 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:36639 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725856AbfFCIQ0 (ORCPT ); Mon, 3 Jun 2019 04:16:26 -0400 Received: by mail-wr1-f68.google.com with SMTP id n4so7935967wrs.3; Mon, 03 Jun 2019 01:16:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:cc:references:from:openpgp:autocrypt:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=4bw+bduVoO24yS9/ugPSh679fDtpvt1k54ZmtZYvvDY=; b=dDN/25OfphVpFdmx2Jm0doKnu8+atN05cNm6KEHVU78DF2cfkZvcbDm9vuIOBTJsMV /k4tPgB8YVdkX1TWlDmIxkriGJarPJy13VBkSL/KFkNLTowFfrejB5hoSQ0P6nYasBwg vmowOIYLourtfEbWaaUvSg3cfGd4Z7qdaw204JicI/2YqtVeF9hPfNRWX4EjVESLP5D7 8gIn5taxacoMd/mKQ3A40WMYCS5N62j9EzS21F4CPVO5u/wBjQD9gIPYeTwgVZXjphoV wZXcsnTq3pS0QP0Ued7mPZR3fCAqtLrUNheK089/2WOIWYB3Rf9HL9zXIwJ3i43PrAOb LyUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:cc:references:from:openpgp :autocrypt:message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=4bw+bduVoO24yS9/ugPSh679fDtpvt1k54ZmtZYvvDY=; b=UCn+vh6YUacOOU6ns53sAkE7iV/DB1lbvR7YG2vxoKMDV2FMdvNFJRqYmoAgT/akPW z3x1zNFJhpvCRP7N3FmlZ8Ao4NHsfEHJKEhB3njVN2h5ofquhrA93+RHKWmmZky7gjJU KhNm1AG5oOnECIM1eHQSuoRwtz0lxqXmiYoe2ceZhc8NAisBYCFLI7cPPaCl9+pk5Hsk YTxURZ551Mx7WVU+G1iSFKUwg39n/5f8rk+BH6A1WwQOepEXOWuFWg6HhnaObLHphwPQ nb/Ze6utmszoiYOSi47M3Loqppd6jiPPQK3poI6f7mDNCLEqrLU+OKuiY/CcQ8jMz/er +ctw== X-Gm-Message-State: APjAAAXO7TcKd4GbJ87Csq+342K6I6smyscYJ6qBwikTnLtPR0ocOr3J 81usIA8y/i2I5ki8PjmrWHw= X-Received: by 2002:adf:e2c8:: with SMTP id d8mr1435179wrj.14.1559549783866; Mon, 03 Jun 2019 01:16:23 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:d43d:6da3:9364:a775? ([2001:b07:6468:f312:d43d:6da3:9364:a775]) by smtp.googlemail.com with ESMTPSA id 197sm13547920wma.36.2019.06.03.01.16.22 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Mon, 03 Jun 2019 01:16:22 -0700 (PDT) Subject: Re: [PATCH 1/2] scsi_host: add support for request batching To: Ming Lei Cc: Linux Kernel Mailing List , KVM General , jejb@linux.ibm.com, "Martin K. Petersen" , Linux SCSI List , Stefan Hajnoczi References: <20190530112811.3066-1-pbonzini@redhat.com> <20190530112811.3066-2-pbonzini@redhat.com> From: Paolo Bonzini Openpgp: preference=signencrypt Autocrypt: addr=pbonzini@redhat.com; keydata= mQHhBFRCcBIBDqDGsz4K0zZun3jh+U6Z9wNGLKQ0kSFyjN38gMqU1SfP+TUNQepFHb/Gc0E2 CxXPkIBTvYY+ZPkoTh5xF9oS1jqI8iRLzouzF8yXs3QjQIZ2SfuCxSVwlV65jotcjD2FTN04 hVopm9llFijNZpVIOGUTqzM4U55sdsCcZUluWM6x4HSOdw5F5Utxfp1wOjD/v92Lrax0hjiX DResHSt48q+8FrZzY+AUbkUS+Jm34qjswdrgsC5uxeVcLkBgWLmov2kMaMROT0YmFY6A3m1S P/kXmHDXxhe23gKb3dgwxUTpENDBGcfEzrzilWueOeUWiOcWuFOed/C3SyijBx3Av/lbCsHU Vx6pMycNTdzU1BuAroB+Y3mNEuW56Yd44jlInzG2UOwt9XjjdKkJZ1g0P9dwptwLEgTEd3Fo UdhAQyRXGYO8oROiuh+RZ1lXp6AQ4ZjoyH8WLfTLf5g1EKCTc4C1sy1vQSdzIRu3rBIjAvnC tGZADei1IExLqB3uzXKzZ1BZ+Z8hnt2og9hb7H0y8diYfEk2w3R7wEr+Ehk5NQsT2MPI2QBd wEv1/Aj1DgUHZAHzG1QN9S8wNWQ6K9DqHZTBnI1hUlkp22zCSHK/6FwUCuYp1zcAEQEAAbQj UGFvbG8gQm9uemluaSA8cGJvbnppbmlAcmVkaGF0LmNvbT6JAg0EEwECACMFAlRCcBICGwMH CwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAAKCRB+FRAMzTZpsbceDp9IIN6BIA0Ol7MoB15E 11kRz/ewzryFY54tQlMnd4xxfH8MTQ/mm9I482YoSwPMdcWFAKnUX6Yo30tbLiNB8hzaHeRj jx12K+ptqYbg+cevgOtbLAlL9kNgLLcsGqC2829jBCUTVeMSZDrzS97ole/YEez2qFpPnTV0 VrRWClWVfYh+JfzpXmgyhbkuwUxNFk421s4Ajp3d8nPPFUGgBG5HOxzkAm7xb1cjAuJ+oi/K CHfkuN+fLZl/u3E/fw7vvOESApLU5o0icVXeakfSz0LsygEnekDbxPnE5af/9FEkXJD5EoYG SEahaEtgNrR4qsyxyAGYgZlS70vkSSYJ+iT2rrwEiDlo31MzRo6Ba2FfHBSJ7lcYdPT7bbk9 AO3hlNMhNdUhoQv7M5HsnqZ6unvSHOKmReNaS9egAGdRN0/GPDWr9wroyJ65ZNQsHl9nXBqE AukZNr5oJO5vxrYiAuuTSd6UI/xFkjtkzltG3mw5ao2bBpk/V/YuePrJsnPFHG7NhizrxttB nTuOSCMo45pfHQ+XYd5K1+Cv/NzZFNWscm5htJ0HznY+oOsZvHTyGz3v91pn51dkRYN0otqr bQ4tlFFuVjArBZcapSIe6NV8C4cEiSS5AQ0EVEJxcwEIAK+nUrsUz3aP2aBjIrX3a1+C+39R nctpNIPcJjFJ/8WafRiwcEuLjbvJ/4kyM6K7pWUIQftl1P8Woxwb5nqL7zEFHh5I+hKS3haO 5pgco//V0tWBGMKinjqntpd4U4Dl299dMBZ4rRbPvmI8rr63sCENxTnHhTECyHdGFpqSzWzy 97rH68uqMpxbUeggVwYkYihZNd8xt1+lf7GWYNEO/QV8ar/qbRPG6PEfiPPHQd/sldGYavmd //o6TQLSJsvJyJDt7KxulnNT8Q2X/OdEuVQsRT5glLaSAeVAABcLAEnNgmCIGkX7TnQF8a6w gHGrZIR9ZCoKvDxAr7RP6mPeS9sAEQEAAYkDEgQYAQIACQUCVEJxcwIbAgEpCRB+FRAMzTZp scBdIAQZAQIABgUCVEJxcwAKCRC/+9JfeMeug/SlCACl7QjRnwHo/VzENWD9G2VpUOd9eRnS DZGQmPo6Mp3Wy8vL7snGFBfRseT9BevXBSkxvtOnUUV2YbyLmolAODqUGzUI8ViF339poOYN i6Ffek0E19IMQ5+CilqJJ2d5ZvRfaq70LA/Ly9jmIwwX4auvXrWl99/2wCkqnWZI+PAepkcX JRD4KY2fsvRi64/aoQmcxTiyyR7q3/52Sqd4EdMfj0niYJV0Xb9nt8G57Dp9v3Ox5JeWZKXS krFqy1qyEIypIrqcMbtXM7LSmiQ8aJRM4ZHYbvgjChJKR4PsKNQZQlMWGUJO4nVFSkrixc9R Z49uIqQK3b3ENB1QkcdMg9cxsB0Onih8zR+Wp1uDZXnz1ekto+EivLQLqvTjCCwLxxJafwKI bqhQ+hGR9jF34EFur5eWt9jJGloEPVv0GgQflQaE+rRGe+3f5ZDgRe5Y/EJVNhBhKcafcbP8 MzmLRh3UDnYDwaeguYmxuSlMdjFL96YfhRBXs8tUw6SO9jtCgBvoOIBDCxxAJjShY4KIvEpK b2hSNr8KxzelKKlSXMtB1bbHbQxiQcerAipYiChUHq1raFc3V0eOyCXK205rLtknJHhM5pfG 6taABGAMvJgm/MrVILIxvBuERj1FRgcgoXtiBmLEJSb7akcrRlqe3MoPTntSTNvNzAJmfWhd SvP0G1WDLolqvX0OtKMppI91AWVu72f1kolJg43wbaKpRJg1GMkKEI3H+jrrlTBrNl/8e20m TElPRDKzPiowmXeZqFSS1A6Azv0TJoo9as+lWF+P4zCXt40+Zhh5hdHO38EV7vFAVG3iuay6 7ToF8Uy7tgc3mdH98WQSmHcn/H5PFYk3xTP3KHB7b0FZPdFPQXBZb9+tJeZBi9gMqcjMch+Y R8dmTcQRQX14bm5nXlBF7VpSOPZMR392LY7wzAvRdhz7aeIUkdO7VelaspFk2nT7wOj1Y6uL nRxQlLkBDQRUQnHuAQgAx4dxXO6/Zun0eVYOnr5GRl76+2UrAAemVv9Yfn2PbDIbxXqLff7o yVJIkw4WdhQIIvvtu5zH24iYjmdfbg8iWpP7NqxUQRUZJEWbx2CRwkMHtOmzQiQ2tSLjKh/c HeyFH68xjeLcinR7jXMrHQK+UCEw6jqi1oeZzGvfmxarUmS0uRuffAb589AJW50kkQK9VD/9 QC2FJISSUDnRC0PawGSZDXhmvITJMdD4TjYrePYhSY4uuIV02v028TVAaYbIhxvDY0hUQE4r 8ZbGRLn52bEzaIPgl1p/adKfeOUeMReg/CkyzQpmyB1TSk8lDMxQzCYHXAzwnGi8WU9iuE1P 0wARAQABiQHzBBgBAgAJBQJUQnHuAhsMAAoJEH4VEAzNNmmxp1EOoJy0uZggJm7gZKeJ7iUp eX4eqUtqelUw6gU2daz2hE/jsxsTbC/w5piHmk1H1VWDKEM4bQBTuiJ0bfo55SWsUNN+c9hh IX+Y8LEe22izK3w7mRpvGcg+/ZRG4DEMHLP6JVsv5GMpoYwYOmHnplOzCXHvmdlW0i6SrMsB Dl9rw4AtIa6bRwWLim1lQ6EM3PWifPrWSUPrPcw4OLSwFk0CPqC4HYv/7ZnASVkR5EERFF3+ 6iaaVi5OgBd81F1TCvCX2BEyIDRZLJNvX3TOd5FEN+lIrl26xecz876SvcOb5SL5SKg9/rCB ufdPSjojkGFWGziHiFaYhbuI2E+NfWLJtd+ZvWAAV+O0d8vFFSvriy9enJ8kxJwhC0ECbSKF Y+W1eTIhMD3aeAKY90drozWEyHhENf4l/V+Ja5vOnW+gCDQkGt2Y1lJAPPSIqZKvHzGShdh8 DduC0U3xYkfbGAUvbxeepjgzp0uEnBXfPTy09JGpgWbg0w91GyfT/ujKaGd4vxG2Ei+MMNDm S1SMx7wu0evvQ5kT9NPzyq8R2GIhVSiAd2jioGuTjX6AZCFv3ToO53DliFMkVTecLptsXaes uUHgL9dKIfvpm+rNXRn9wAwGjk0X/A== Message-ID: Date: Mon, 3 Jun 2019 10:16:21 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 31/05/19 05:27, Ming Lei wrote: > It should be fine to implement scsi_commit_rqs() as: > > if (shost->hostt->commit_rqs) > shost->hostt->commit_rqs(shost, hctx->queue_num); > > then scsi_mq_ops_no_commit can be saved. > > Because .commit_rqs() is only called when BLK_STS_*_RESOURCE is > returned from scsi_queue_rq(), at that time shost->hostt->commit_rqs should > have been hit from cache given .queuecommand is called via > host->hostt->queuecommand. This is not about d-cache, it's about preserving the heuristics that blk-mq applies depending on whether commit_rqs is there or not. Paolo