From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 29B2E72 for ; Fri, 13 Aug 2021 07:30:04 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 958DD6736F; Fri, 13 Aug 2021 09:29:55 +0200 (CEST) Date: Fri, 13 Aug 2021 09:29:55 +0200 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Christoph Hellwig , Dan Williams , Matthew Wilcox , Andreas Gruenbacher , Shiyang Ruan , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, nvdimm@lists.linux.dev, cluster-devel@redhat.com Subject: Re: [PATCH 11/30] iomap: add the new iomap_iter model Message-ID: <20210813072955.GA27278@lst.de> References: <20210809061244.1196573-1-hch@lst.de> <20210809061244.1196573-12-hch@lst.de> <20210811003118.GT3601466@magnolia> <20210811053856.GA1934@lst.de> <20210811191708.GF3601443@magnolia> <20210812064914.GA27145@lst.de> <20210812182017.GX3601466@magnolia> Precedence: bulk X-Mailing-List: nvdimm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210812182017.GX3601466@magnolia> User-Agent: Mutt/1.5.17 (2007-11-01) On Thu, Aug 12, 2021 at 11:20:17AM -0700, Darrick J. Wong wrote: > The history of the gluecode that enables us to walk a bunch of extent > mappings. In the beginning it was the _apply function, but now in our > spectre-weary world, you've switched it to a direct loop to reduce the > number of indirect calls in the hot path by 30-50%. > > As you correctly point out, there's no /code/ shared by the two > implementations, but Dave and I would like to preserve the continuity > from one to the next. > > > > I'll send the updated patches as replies to this series to avoid > > > spamming the list, since I also have a patchset of bugfixes to send out > > > and don't want to overwhelm everyone. > > > > Just as a clear statement: I think this dance is obsfucation and doesn't > > help in any way. But if that's what it takes.. > > I /would/ appreciate it if you'd rvb (or at least ack) patch 31 so I can > get the 5.15 iomap changes finalized next week. Pretty please? :) I think it is a really stupid idea, so certainly no rvb or ack from me. If you feel you want to do it this way go ahead, but I do not in any way approve of it.