From mboxrd@z Thu Jan 1 00:00:00 1970 From: keith.busch@intel.com (Keith Busch) Date: Mon, 28 Jan 2019 16:24:24 -0700 Subject: [PATCH v2 0/4] Write-hint for FS journal In-Reply-To: <20190128124709.GB27972@quack2.suse.cz> References: <1547047861-7271-1-git-send-email-joshi.k@samsung.com> <20190125162353.GA11210@localhost.localdomain> <20190128124709.GB27972@quack2.suse.cz> Message-ID: <20190128232423.GD15302@localhost.localdomain> On Mon, Jan 28, 2019@04:47:09AM -0800, Jan Kara wrote: > On Fri 25-01-19 09:23:53, Keith Busch wrote: > > On Wed, Jan 09, 2019@09:00:57PM +0530, Kanchan Joshi wrote: > > > Towards supporing write-hints/streams for filesystem journal. > > > > > > Here is the v1 patch for background - > > > https://marc.info/?l=linux-fsdevel&m=154444637519020&w=2 > > > > > > Changes since v1: > > > - introduce four more hints for in-kernel use, as recommended by Dave chinner > > > & Jens axboe. This isolates kernel-mode hints from user-mode ones. > > > > The nvme driver disables streams if the controller doesn't support > > BLK_MAX_WRITE_HINT number of streams, so this series breaks the feature > > for controllers that only support up to 4. > > Right. Do you know if there are such controllers? Or are you just afraid > that there could be? I've asked around, and the concensus I received is all currently support at least 8, but they couldn't say if that would be true for potential lower budget products. Can we implement a reasonable fallback to use what's available?