From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f41.google.com (mail-io1-f41.google.com [209.85.166.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 54FA879FF for ; Wed, 2 Aug 2023 15:36:35 +0000 (UTC) Received: by mail-io1-f41.google.com with SMTP id ca18e2360f4ac-790af3bfa5cso35237839f.1 for ; Wed, 02 Aug 2023 08:36:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1690990594; x=1691595394; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=673FNT9+5mnaLVg5PRS120UPJdmtYWKDCkh6MjsqAGk=; b=R4amrDn6vllXAmBsGQnv9oHwNxdRbsqsTtZSo7STLE0X4xCcT2NH/8UwHo1w3NE7X9 yLybNlu8wgc7zT+0qwXccOSODFeIOgs9wa1sY9SzjmfxegGbJreQCHQtUdQv+n3auNUS 0LHE53TlHXsqs9NO32h18jJeakxACNmc/nwB0Q27z1rgXh2qGIjMZcv+4YTcZ74DPc0g vKos/2ByJZx1J4oBOK2OJ2b6JtmqCsspCzSwcI8OSlGURpj0+hMyhHREQ6/P0ujI9eKK tMtjUzcu5P54T2iMMxojTWO//ZVjDzPDWhHmhPBIsYvOkYh2mSxgIweS8G5VtMk5FFpG tEkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690990594; x=1691595394; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=673FNT9+5mnaLVg5PRS120UPJdmtYWKDCkh6MjsqAGk=; b=Mknil4tUHcW4AMe+fsOtCQ7T0i3BJ5o296vpf+uHFu5eVtBOxHk7v2MjF/zSbCkDK5 iLqWqVvmd/A/ePnFLwUXPvOwooqbYa0oIwvTFbMYstv9HWHYP9kt0GFCwg8nH2/knSiO qhSW3TgWhFtHmhe9/uPAQaTLa3HnYQ1MhyLCXYcfmeraIaf9cWprKbTxgZHjt1CUnB1d ovS0bKBFH7ZUX7VjQacipfc9ss5L7T/Mdq7VyoidfRr1Wx1DftArzAmCDnAfFy9V7l7d 2dGfSN5jjeIP3lWLZ2mVyyJEZRA19YrKIHHBXM+1Jb1fa+9xTsZZyml3sWeXTTz900Is eCRw== X-Gm-Message-State: ABy/qLYea7h4rmoiujeCspaqmgU599pEvG9wCJ7Ag/2IEF34QoB9CN9P UgQnwQYNgwFCHieueEtBpIT8knVW2vK2oPp+GuU= X-Google-Smtp-Source: APBJJlGUkAAAMCsRyqhq/PIoWTsQaXC7gGA1eoObLajsTDL34SrB7j0y4Xe/8ukTb5Tru29rdlT26A== X-Received: by 2002:a05:6602:2b91:b0:77a:ee79:652 with SMTP id r17-20020a0566022b9100b0077aee790652mr18610565iov.1.1690990594272; Wed, 02 Aug 2023 08:36:34 -0700 (PDT) Received: from [192.168.1.94] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id m18-20020a056638225200b0042b08954dc3sm4351434jas.33.2023.08.02.08.36.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Aug 2023 08:36:33 -0700 (PDT) Message-ID: <17c5d907-d276-bffc-17ca-d796156a2b78@kernel.dk> Date: Wed, 2 Aug 2023 09:36:32 -0600 Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.13.1 Subject: Re: [PATCH V2 1/1] pmem: set QUEUE_FLAG_NOWAIT Content-Language: en-US To: Christoph Hellwig , Chaitanya Kulkarni Cc: Jeff Moyer , "dan.j.williams@intel.com" , "vishal.l.verma@intel.com" , "dave.jiang@intel.com" , "ira.weiny@intel.com" , "nvdimm@lists.linux.dev" , linux-block@vger.kernel.org References: <20230731224617.8665-1-kch@nvidia.com> <20230731224617.8665-2-kch@nvidia.com> <20230801155943.GA13111@lst.de> <0a2d86d6-34a1-0c8d-389c-1dc2f886f108@nvidia.com> <20230802123010.GB30792@lst.de> From: Jens Axboe In-Reply-To: <20230802123010.GB30792@lst.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/2/23 6:30?AM, Christoph Hellwig wrote: > Given that pmem simply loops over an arbitrarily large bio I think > we also need a threshold for which to allow nowait I/O. While it > won't block for giant I/Os, doing all of them in the submitter > context isn't exactly the idea behind the nowait I/O. You can do a LOT of looping over a giant bio and still come out way ahead compared to needing to punt to a different thread. So I do think it's the right choice. But I'm making assumptions here on what it looks like, as I haven't seen the patch... > Btw, please also always add linux-block to the Cc list for block > driver patches that are even the slightest bit about the block > layer interface. Indeed. Particularly for these nowait changes, as some of them have been pretty broken in the past. -- Jens Axboe