From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211] helo=newverein.lst.de) by merlin.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gCfEc-0006uH-Pm for linux-um@lists.infradead.org; Wed, 17 Oct 2018 06:23:11 +0000 Date: Wed, 17 Oct 2018 08:21:51 +0200 From: Christoph Hellwig Subject: Re: [PATCH, RFC] ubd: remove use of blk_rq_map_sg Message-ID: <20181017062150.GA22028@lst.de> References: <20181015065637.1860-1-hch@lst.de> <2132215.oDDApMmxLa@blindfold> <4bd66e34-acc5-053f-888e-d4e58c3cf440@kernel.dk> <5155064.LnyfiXsD0j@blindfold> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: Jens Axboe Cc: Richard Weinberger , linux-um@lists.infradead.org, linux-block@vger.kernel.org, dwalter@google.com, Christoph Hellwig , anton.ivanov@cambridgegreys.com On Tue, Oct 16, 2018 at 08:26:31AM -0600, Jens Axboe wrote: > > Yes. Shall I send a patch with your suggestion or will you? > > Christoph should just fold it in, the bug only exists after his > change to it. Sorry, I missed what suggestion we had. Is that the patch form Jens earlier? > > > I have one more question, in your first conversion you set queue_depth to 2. > > How does one know this value? > > My conversion has 64, which is more or less an educated guess... ;) > > 64 is most likely just fine. Some drivers rely on having 1 in flight and > it's easier to manage to just let blk-mq take care of that. Outside of that, > there aren't any magic values. We should probably just use BLKDEV_MAX_RQ > for ones that don't have a specific hw limit or need. Is a queue depth > 1 actually safe for ubd? There are some odd global variables tracking struct io_thread_req. _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um