From: Oscar Salvador <osalvador@suse.de>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Michal Hocko <mhocko@kernel.org>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
David Hildenbrand <david@redhat.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [RFC 1/5] mm, page_alloc: clean up pageset high and batch update
Date: Thu, 10 Sep 2020 10:31:20 +0200 [thread overview]
Message-ID: <20200910083116.GA2285@linux> (raw)
In-Reply-To: <20200907163628.26495-2-vbabka@suse.cz>
On Mon, Sep 07, 2020 at 06:36:24PM +0200, Vlastimil Babka wrote:
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> for_each_possible_cpu(cpu)
> - setup_pageset(&per_cpu(boot_pageset, cpu), 0);
> + setup_pageset(&per_cpu(boot_pageset, cpu));
This is not really anything important but I realized we have like 7 functions
messing with pcp lists, and everytime I try to follow them my head spins.
Since setup_pageset is only being called here, could we replace it by the
pageset_init and pageset_update?
(As I said, not important and probably a matter of taste. I just think that
having so many mini functions around is not always cool,
e.g: setup_zone_pageset->zone_pageset_init)
> -/*
> - * pageset_set_high() sets the high water mark for hot per_cpu_pagelist
> - * to the value high for the pageset p.
> - */
> -static void pageset_set_high(struct per_cpu_pageset *p,
> - unsigned long high)
> -{
> - unsigned long batch = max(1UL, high / 4);
> - if ((high / 4) > (PAGE_SHIFT * 8))
> - batch = PAGE_SHIFT * 8;
> -
> - pageset_update(&p->pcp, high, batch);
> + pageset_update(&p->pcp, 0, 1);
> }
Could we restore the comment we had in pageset_set_high, and maybe
update it to match this new function? I think it would be useful.
>
> static void pageset_set_high_and_batch(struct zone *zone,
> - struct per_cpu_pageset *pcp)
> + struct per_cpu_pageset *p)
> {
> - if (percpu_pagelist_fraction)
> - pageset_set_high(pcp,
> - (zone_managed_pages(zone) /
> - percpu_pagelist_fraction));
> - else
> - pageset_set_batch(pcp, zone_batchsize(zone));
> + unsigned long new_high;
> + unsigned long new_batch;
> + int fraction = READ_ONCE(percpu_pagelist_fraction);
Why the READ_ONCE? In case there is a parallel update so things to get
messed up?
as I said, I'd appreciate a comment in pageset_set_high_and_batch to be
restored and updated, otherwise:
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Thanks
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2020-09-10 8:32 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 16:36 [RFC 0/5] disable pcplists during page isolation Vlastimil Babka
2020-09-07 16:36 ` [RFC 1/5] mm, page_alloc: clean up pageset high and batch update Vlastimil Babka
2020-09-10 8:31 ` Oscar Salvador [this message]
2020-09-10 8:34 ` Oscar Salvador
2020-09-10 10:47 ` David Hildenbrand
2020-09-17 16:05 ` Vlastimil Babka
2020-09-07 16:36 ` [RFC 2/5] mm, page_alloc: calculate pageset high and batch once per zone Vlastimil Babka
2020-09-10 9:00 ` Oscar Salvador
2020-09-10 10:56 ` David Hildenbrand
2020-09-07 16:36 ` [RFC 3/5] mm, page_alloc(): remove setup_pageset() Vlastimil Babka
2020-09-10 9:23 ` Oscar Salvador
2020-09-10 9:57 ` Oscar Salvador
2020-09-18 9:37 ` Vlastimil Babka
2020-09-10 11:00 ` David Hildenbrand
2020-09-07 16:36 ` [RFC 4/5] mm, page_alloc: cache pageset high and batch in struct zone Vlastimil Babka
2020-09-10 11:30 ` Oscar Salvador
2020-09-18 12:02 ` Vlastimil Babka
2020-09-07 16:36 ` [RFC 5/5] mm, page_alloc: disable pcplists during page isolation Vlastimil Babka
2020-09-09 10:48 ` Vlastimil Babka
2020-09-09 11:36 ` Michal Hocko
2020-09-09 11:44 ` David Hildenbrand
2020-09-09 12:57 ` David Hildenbrand
2020-09-09 11:55 ` Vlastimil Babka
2020-09-10 10:29 ` David Hildenbrand
2020-09-10 11:05 ` Vlastimil Babka
2020-09-10 12:42 ` David Hildenbrand
2020-09-09 12:53 ` Pavel Tatashin
2020-09-08 18:29 ` [RFC 0/5] " David Hildenbrand
2020-09-09 10:54 ` Vlastimil Babka
2020-09-09 11:27 ` osalvador
2020-09-09 11:29 ` David Hildenbrand
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=20200910083116.GA2285@linux \
--to=osalvador@suse.de \
--cc=david@redhat.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=pasha.tatashin@soleen.com \
--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).