From: David Hildenbrand <david@redhat.com>
To: Mel Gorman <mgorman@techsingularity.net>, Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Oscar Salvador <osalvador@suse.de>,
"Michael S. Tsirkin" <mst@redhat.com>,
Vlastimil Babka <vbabka@suse.cz>,
Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH] mm/memory_hotplug: Make unpopulated zones PCP structures unreachable during hot remove
Date: Fri, 9 Apr 2021 21:05:25 +0200 [thread overview]
Message-ID: <9317b74e-f706-27eb-6e5c-3dc0f3ee98b8@redhat.com> (raw)
In-Reply-To: <20210409151259.GP3697@techsingularity.net>
>>> zone_pcp_reset still needs to exist to drain the remaining vmstats or
>>> it'll break 5a883813845a ("memory-hotplug: fix zone stat
>>> mismatch").
>>
>> Are you sure we are reseting vmstats in the hotremove. I do not see
>> anything like that. Maybe this was needed at the time. I will double
>> check.
>
> zone_pcp_reset calls drain_zonestat to apply the per-cpu vmstat deltas
> to the atomic per-zone and global stats.
>
> If anything, the minimal "fix" is to simply delete IRQ disable/enable on
> the grounds that IRQs protect nothing and assume the existing hotplug
> paths guarantees the PCP cannot be used after zone_pcp_enable(). That
^ that sounds sane to me
> should be the case already because all the pages have been freed and
> there is nothing to even put into the PCPs but I worried that the PCP
> structure itself might still be reachable even if it's useless which is
> why I freed the structure once they could not be reached via zonelists.
>
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-04-09 19:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-09 12:09 [PATCH] mm/memory_hotplug: Make unpopulated zones PCP structures unreachable during hot remove Mel Gorman
2021-04-09 12:42 ` Michal Hocko
2021-04-09 12:48 ` Michal Hocko
2021-04-09 13:42 ` Mel Gorman
2021-04-09 14:37 ` Michal Hocko
2021-04-09 15:12 ` Mel Gorman
2021-04-09 19:05 ` David Hildenbrand [this message]
2021-04-10 7:25 ` Michal Hocko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=9317b74e-f706-27eb-6e5c-3dc0f3ee98b8@redhat.com \
--to=david@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=alexander.h.duyck@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=mst@redhat.com \
--cc=osalvador@suse.de \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).