Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965810AbcLWNKe (ORCPT ); Fri, 23 Dec 2016 08:10:34 -0500 Received: from mail-qt0-f195.google.com ([209.85.216.195]:36386 "EHLO mail-qt0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755607AbcLWNKd (ORCPT ); Fri, 23 Dec 2016 08:10:33 -0500 MIME-Version: 1.0 In-Reply-To: References: <20161126201534.5d5e338f678b478e7a7b8dc3@gmail.com> <20161129143916.f24c141c1a264bad1220031e@linux-foundation.org> From: Dan Streetman Date: Fri, 23 Dec 2016 08:09:51 -0500 X-Google-Sender-Auth: 1a87iJCnz_qyVeQQi0cEZ62pnuc Message-ID: Subject: Re: [PATCH 0/2] z3fold fixes To: Vitaly Wool Cc: Andrew Morton , Linux-MM , linux-kernel , Arnd Bergmann , Dan Carpenter Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id uBNDAdnV025304 Content-Length: 4758 Lines: 101 On Thu, Dec 22, 2016 at 6:04 PM, Vitaly Wool wrote: > On Thu, Dec 22, 2016 at 10:55 PM, Dan Streetman wrote: >> On Sun, Dec 18, 2016 at 3:15 AM, Vitaly Wool wrote: >>> On Tue, Nov 29, 2016 at 11:39 PM, Andrew Morton >>> wrote: >>>> On Tue, 29 Nov 2016 17:33:19 -0500 Dan Streetman wrote: >>>> >>>>> On Sat, Nov 26, 2016 at 2:15 PM, Vitaly Wool wrote: >>>>> > Here come 2 patches with z3fold fixes for chunks counting and locking. As commit 50a50d2 ("z3fold: don't fail kernel build is z3fold_header is too big") was NAK'ed [1], I would suggest that we removed that one and the next z3fold commit cc1e9c8 ("z3fold: discourage use of pages that weren't compacted") and applied the coming 2 instead. >>>>> >>>>> Instead of adding these onto all the previous ones, could you redo the >>>>> entire z3fold series? I think it'll be simpler to review the series >>>>> all at once and that would remove some of the stuff from previous >>>>> patches that shouldn't be there. >>>>> >>>>> If that's ok with Andrew, of course, but I don't think any of the >>>>> z3fold patches have been pushed to Linus yet. >>>> >>>> Sounds good to me. I had a few surprise rejects when merging these >>>> two, which indicates that things might be out of sync. >>>> >>>> I presently have: >>>> >>>> z3fold-limit-first_num-to-the-actual-range-of-possible-buddy-indexes.patch >>>> z3fold-make-pages_nr-atomic.patch >>>> z3fold-extend-compaction-function.patch >>>> z3fold-use-per-page-spinlock.patch >>>> z3fold-discourage-use-of-pages-that-werent-compacted.patch >>>> z3fold-fix-header-size-related-issues.patch >>>> z3fold-fix-locking-issues.patch >>> >>> My initial suggestion was to have it the following way: >>> z3fold-limit-first_num-to-the-actual-range-of-possible-buddy-indexes.patch >> >> this is a good one, acked by both of us; it should stay and go upstream to Linus >> >>> z3fold-make-pages_nr-atomic.patch >> >> the change itself looks ok and I acked it, but as Andrew commented the >> log says nothing about why it's being changed; the atomic function is >> slower so the log should explain why it's being changed; anyone >> reviewing the log history won't know why you made the change, and the >> change all by itself is a step backwards in performance. >> >>> z3fold-extend-compaction-function.patch >> >> this explictly has a bug in it that's fixed in one of the later >> patches; instead, this should be fixed up and resent. >> >>> z3fold-use-per-page-spinlock.patch >> >> i should have explicitly nak'ed this, as not only did it add a bug >> (fixed by the the other 'fix-' patch below) but its design should be >> replaced by kref counting, which your latest patch is working >> towards... >> >>> z3fold-fix-header-size-related-issues.patch >>> z3fold-fix-locking-issues.patch >> >> and these fix the known problems in the previous patches. >> >>> >>> I would prefer to keep the fix-XXX patches separate since e. g. >>> z3fold-fix-header-size-related-issues.patch concerns also the problems >>> that have been in the code for a while now. I am ok with folding these >>> into the relevant main patches but once again, given that some fixes >>> are related to the code that is already merged, I don't see why it >>> would be better. >> >> none of those patches are "merged", the last z3fold patch in Linus' >> tree is 43afc194 from June. Just because they're in Andrew's mmotm >> queue (and/or linux-next) doesn't mean they are going to be >> merged...(correct me please if I'm wrong there Andrew) > > that I do understand, however, > z3fold-fix-header-size-related-issues.patch fixes the off-by-one issue > present in the code that is in Linus's tree too. sorry, I just looked at this in mmotm and it does look good; I must have been confused because this was sent as part of a 2-patch series, but the two patches don't seem related :-) > >> So as you can see by my patch-by-patch breakdown, almost all of them >> need changes based on feedback from various people. And they are all >> related - your goal is to improve z3fold performance, right? IMHO >> they should be sent as a single patch series with that goal in the >> cover letter, including specific details and numbers about how the >> series does improve performance. > > but that is a good idea anyway, the only thing i\m not sure about is > whether it makes sense to fold > z3fold-fix-header-size-related-issues.patch into another or not. no that looks ok to separate, it's a standalone bugfix. I'm just saying, for the patches where problems were identified already, resend them with the patches fixed; and any that are related, send as a series. > > ~vitaly