From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [RFC PATCH 00/32] separate operations from flags in the bio/request structs Date: Wed, 11 Nov 2015 12:37:20 -0500 Message-ID: <20151111173719.GB12236@redhat.com> References: <1446654807-6935-1-git-send-email-mchristi@redhat.com> <563A36FC.6010001@sandisk.com> <563A3813.5010604@cs.wisc.edu> <20151107102309.GE12117@infradead.org> <5642F3F4.2060007@cs.wisc.edu> <20151111112846.GA358@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20151111112846.GA358-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: drbd-dev-bounces-cunTk1MwBs8qoQakbn7OcQ@public.gmane.org Errors-To: drbd-dev-bounces-cunTk1MwBs8qoQakbn7OcQ@public.gmane.org To: Christoph Hellwig Cc: Mike Christie , linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, device-mapper development , linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, drbd-dev-cunTk1MwBs8qoQakbn7OcQ@public.gmane.org List-Id: linux-scsi@vger.kernel.org On Wed, Nov 11 2015 at 6:28am -0500, Christoph Hellwig wrote: > On Wed, Nov 11, 2015 at 01:53:24AM -0600, Mike Christie wrote: > > We no longer have the bvec merge functions so the original reason given > > in the thread/patch Bart referenced is no longer valid. > > > > Offlist it was suggested that dropping the argument from submit_bio > > might still improve performance, but I modified xfs and dm and did some > > testing and did not see anything. > > > > So the change is not needed, and it would only be done because people > > feel it would improve the interface. > > I would defintively prefer the changed interface, and to me it also > looks like it would make your overall patch simpler. If you disagree > feel free to keep it as-is for now and I'll do another pass later. The less churn the better. But honestly, not quite following the logic on why all this flag-day churn is needed. BUT if it needs to happen, because we'll soon hit a wall on supported operations via REQ_*, now is as good a time as any -- but best to limit the change to the flags IMHO.