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Date: Sun, 5 Feb 2017 00:59:47 -0800
From: Christoph Hellwig <hch@infradead.org>
To: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net,
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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>
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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 dіscard
code, and I'd like to make sure we get common infrastructure instead
of local hacks.