From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sun, 5 Feb 2017 00:59:47 -0800 From: Christoph Hellwig To: Jaegeuk Kim Cc: Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, axboe@kernel.dk Subject: Re: [PATCH 5/6] f2fs: add a kernel thread to issue discard commands asynchronously Message-ID: <20170205085947.GA25319@infradead.org> References: <20170112224407.54026-1-jaegeuk@kernel.org> <20170112224407.54026-5-jaegeuk@kernel.org> <20170113080159.GB31777@infradead.org> <20170113191211.GB1301@jaegeuk.local> <20170116173220.GA2199@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170116173220.GA2199@infradead.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Mon, Jan 16, 2017 at 09:32:20AM -0800, Christoph Hellwig wrote: > On Fri, Jan 13, 2017 at 11:12:11AM -0800, Jaegeuk Kim wrote: > > Previously, I've done to issue discard bios asynchronously. But the problem that > > I've got is that was not enough. When testing nvme SSD with noop IO scheduler, > > submit_bio() was blocked at every 8 async discard bios, resulting in very slow > > checkpoint process which blocks most of other FS operations. > > Where does it block? Are you running out of request? What driver is > this on top of? Ping? I'm currently spending a lot of effort on fs and block dÑ–scard code, and I'd like to make sure we get common infrastructure instead of local hacks.