From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f197.google.com (mail-qt0-f197.google.com [209.85.216.197]) by kanga.kvack.org (Postfix) with ESMTP id 8066428026F for ; Fri, 23 Dec 2016 08:10:33 -0500 (EST) Received: by mail-qt0-f197.google.com with SMTP id w39so186366257qtw.0 for ; Fri, 23 Dec 2016 05:10:33 -0800 (PST) Received: from mail-qt0-x243.google.com (mail-qt0-x243.google.com. [2607:f8b0:400d:c0d::243]) by mx.google.com with ESMTPS id c185si1646511qkb.105.2016.12.23.05.10.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 23 Dec 2016 05:10:32 -0800 (PST) Received: by mail-qt0-x243.google.com with SMTP id p16so10914173qta.1 for ; Fri, 23 Dec 2016 05:10:32 -0800 (PST) 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 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: Vitaly Wool Cc: Andrew Morton , Linux-MM , linux-kernel , Arnd Bergmann , Dan Carpenter 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 wrot= e: >>> On Tue, Nov 29, 2016 at 11:39 PM, Andrew Morton >>> wrote: >>>> On Tue, 29 Nov 2016 17:33:19 -0500 Dan Streetman w= rote: >>>> >>>>> On Sat, Nov 26, 2016 at 2:15 PM, Vitaly Wool w= rote: >>>>> > Here come 2 patches with z3fold fixes for chunks counting and locki= ng. 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 th= e >>>>> 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.p= atch >>>> 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.pa= tch >> >> 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 -- 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