From: Mel Gorman <mgorman@techsingularity.net>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Linux-MM <linux-mm@kvack.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>,
Michal Hocko <mhocko@kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/6] mm/page_alloc: Adjust pcp->high after CPU hotplug events
Date: Mon, 24 May 2021 17:01:01 +0100 [thread overview]
Message-ID: <20210524160101.GG30378@techsingularity.net> (raw)
In-Reply-To: <e9061a5c-bbef-e818-94f7-95e21a73a948@intel.com>
On Mon, May 24, 2021 at 08:52:02AM -0700, Dave Hansen wrote:
> > To address your point requires much deeper surgery.
> ...
> > There is value to doing something like this but it's beyond what this
> > series is trying to do and doing the work without introducing regressions
> > would be very difficult.
>
> Agreed, such a solution is outside of the scope of what this set is
> trying to do.
>
> It would be nice to touch on this counter-intuitive property in the
> changelog, and *maybe* add a WARN_ON_ONCE() if we hit an edge case.
> Maybe WARN_ON_ONCE() if pcp->high gets below pcp->batch*SOMETHING.
>
I think it's reasonable to ensure pcp->batch is never above pcp->high so
I have this in zone_highsize now
+ /*
+ * Ensure high is at least batch*4. The multiple is based on the
+ * historical relationship between high and batch.
+ */
+ high = max(high, batch << 2);
Performance tests are running and I'll post a v2 assuming they pass.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2021-05-24 16:09 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 10:28 [RFC PATCH 0/6] Calculate pcp->high based on zone sizes and active CPUs Mel Gorman
2021-05-21 10:28 ` [PATCH 1/6] mm/page_alloc: Delete vm.percpu_pagelist_fraction Mel Gorman
2021-05-21 21:04 ` Dave Hansen
2021-05-21 10:28 ` [PATCH 2/6] mm/page_alloc: Disassociate the pcp->high from pcp->batch Mel Gorman
2021-05-21 21:52 ` Dave Hansen
2021-05-24 8:32 ` Mel Gorman
2021-05-21 10:28 ` [PATCH 3/6] mm/page_alloc: Adjust pcp->high after CPU hotplug events Mel Gorman
2021-05-21 22:13 ` Dave Hansen
2021-05-24 9:07 ` Mel Gorman
2021-05-24 15:52 ` Dave Hansen
2021-05-24 16:01 ` Mel Gorman [this message]
2021-05-21 10:28 ` [PATCH 4/6] mm/page_alloc: Scale the number of pages that are batch freed Mel Gorman
2021-05-21 22:36 ` Dave Hansen
2021-05-24 9:12 ` Mel Gorman
2021-05-21 10:28 ` [PATCH 5/6] mm/page_alloc: Limit the number of pages on PCP lists when reclaim is active Mel Gorman
2021-05-21 22:44 ` Dave Hansen
2021-05-24 9:22 ` Mel Gorman
2021-05-21 10:28 ` [PATCH 6/6] mm/page_alloc: Introduce vm.percpu_pagelist_high_fraction Mel Gorman
2021-05-21 22:57 ` Dave Hansen
2021-05-24 9:25 ` Mel Gorman
2021-05-22 2:19 ` Hillf Danton
2021-05-25 8:01 [PATCH 0/6 v2] Calculate pcp->high based on zone sizes and active CPUs Mel Gorman
2021-05-25 8:01 ` [PATCH 3/6] mm/page_alloc: Adjust pcp->high after CPU hotplug events Mel Gorman
2021-05-28 11:08 ` Vlastimil Babka
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=20210524160101.GG30378@techsingularity.net \
--to=mgorman@techsingularity.net \
--cc=dave.hansen@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=npiggin@gmail.com \
--cc=vbabka@suse.cz \
--cc=willy@infradead.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.