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[172.10.233.147]) by smtp.gmail.com with ESMTPSA id g18sm1235379otq.33.2021.02.25.09.21.16 (version=TLS1 cipher=ECDHE-ECDSA-AES128-SHA bits=128/128); Thu, 25 Feb 2021 09:21:17 -0800 (PST) Date: Thu, 25 Feb 2021 09:21:04 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Roman Gushchin cc: Hugh Dickins , Andrew Morton , Johannes Weiner , Michal Hocko , Vlastimil Babka , linux-mm@kvack.org, kernel-team@fb.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm: vmstat: fix /proc/sys/vm/stat_refresh generating false warnings In-Reply-To: Message-ID: References: <20200730162348.GA679955@carbon.dhcp.thefacebook.com> <20200801011821.GA859734@carbon.dhcp.thefacebook.com> <20200804004012.GA1049259@carbon.dhcp.thefacebook.com> <20200806233804.GB1217906@carbon.dhcp.thefacebook.com> <20200806182555.d7a7fc9853b5a239ffe9f846@linux-foundation.org> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 24 Feb 2021, Roman Gushchin wrote: > On Tue, Feb 23, 2021 at 11:24:23PM -0800, Hugh Dickins wrote: > > On Thu, 6 Aug 2020, Andrew Morton wrote: > > > On Thu, 6 Aug 2020 16:38:04 -0700 Roman Gushchin wrote: > > > > August, yikes, I thought it was much more recent. > > > > > > > > > it seems that Hugh and me haven't reached a consensus here. > > > > Can, you, please, not merge this patch into 5.9, so we would have > > > > more time to find a solution, acceptable for all? > > > > > > No probs. I already had a big red asterisk on it ;) > > > > I've a suspicion that Andrew might be tiring of his big red asterisk, > > and wanting to unload > > mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings.patch > > mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings-fix.patch > > mm-vmstat-fix-proc-sys-vm-stat_refresh-generating-false-warnings-fix-2.patch > > into 5.12. > > > > I would prefer not, and reiterate my Nack: but no great harm will > > befall the cosmos if he overrules that, and it does go through to > > 5.12 - I'll just want to revert it again later. And I do think a > > more straightforward way of suppressing those warnings would be just > > to delete the code that issues them, rather than brushing them under > > a carpet of overtuning. > > I'm actually fine with either option. My only concern is that if somebody > will try to use the hugetlb_cma boot option AND /proc/sys/vm/stat_refresh > together, they will get a false warning and report them to mm@ or will > waste their time trying to debug a non-existing problem. It's not the end > of the world. > We can also make the warning conditional on CONFIG_DEBUG_VM, for example. > > Please, let me know what's your preferred way to go forward. My preferred way forward (for now: since we're all too busy to fix the misbehaving stats) is for Andrew to drop your patch, and I'll post three patches against current 5.12 in a few hours: one to restore the check on the missing NR_VM_NODE_STAT_ITEMS, one to remove the -EINVAL (which upsets test scripts at our end), one to suppress the warning on nr_zone_write_pending, nr_writeback and nr_free_cma. Hugh