From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f200.google.com (mail-ua0-f200.google.com [209.85.217.200]) by kanga.kvack.org (Postfix) with ESMTP id DC16128026B for ; Thu, 22 Dec 2016 18:04:52 -0500 (EST) Received: by mail-ua0-f200.google.com with SMTP id 96so3253835uaq.7 for ; Thu, 22 Dec 2016 15:04:52 -0800 (PST) Received: from mail-vk0-x241.google.com (mail-vk0-x241.google.com. [2607:f8b0:400c:c05::241]) by mx.google.com with ESMTPS id 31si1399873uam.178.2016.12.22.15.04.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Dec 2016 15:04:48 -0800 (PST) Received: by mail-vk0-x241.google.com with SMTP id p9so18995756vkd.1 for ; Thu, 22 Dec 2016 15:04:48 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <20161126201534.5d5e338f678b478e7a7b8dc3@gmail.com> <20161129143916.f24c141c1a264bad1220031e@linux-foundation.org> From: Vitaly Wool Date: Fri, 23 Dec 2016 00:04:47 +0100 Message-ID: Subject: Re: [PATCH 0/2] z3fold fixes Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Dan Streetman Cc: Andrew Morton , Linux-MM , linux-kernel , Arnd Bergmann , Dan Carpenter 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 wr= ote: >>> >>>> On Sat, Nov 26, 2016 at 2:15 PM, Vitaly Wool wr= ote: >>>> > Here come 2 patches with z3fold fixes for chunks counting and lockin= g. 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 c= ompacted") 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.pa= tch >>> 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.pat= ch > > this is a good one, acked by both of us; it should stay and go upstream t= o 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. > 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. ~vitaly -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org