From: Vlastimil Babka <vbabka@suse.cz>
To: Oscar Salvador <osalvador@suse.de>
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 4/5] mm, page_alloc: cache pageset high and batch in struct zone
Date: Fri, 18 Sep 2020 14:02:42 +0200 [thread overview]
Message-ID: <08421531-1df0-3cea-fe44-2e4e30808dfd@suse.cz> (raw)
In-Reply-To: <20200910113046.GA5848@linux>
On 9/10/20 1:30 PM, Oscar Salvador wrote:
> On Mon, Sep 07, 2020 at 06:36:27PM +0200, Vlastimil Babka wrote:
> */
>> -static void setup_pageset(struct per_cpu_pageset *p);
>> +static void pageset_init(struct per_cpu_pageset *p);
>
> this belongs to the respective patches
Right, thanks.
>> -static void zone_set_pageset_high_and_batch(struct zone *zone)
>> +static void zone_set_pageset_high_and_batch(struct zone *zone, bool force_update)
>> {
>> unsigned long new_high;
>> unsigned long new_batch;
>> @@ -6256,6 +6256,14 @@ static void zone_set_pageset_high_and_batch(struct zone *zone)
>> new_batch = max(1UL, 1 * new_batch);
>> }
>>
>> + if (zone->pageset_high != new_high ||
>> + zone->pageset_batch != new_batch) {
>> + zone->pageset_high = new_high;
>> + zone->pageset_batch = new_batch;
>> + } else if (!force_update) {
>> + return;
>> + }
>
> I am probably missimg something obvious, so sorry, but why do we need
> force_update here?
> AFAICS, we only want to call pageset_update() in case zone->pageset_high/batch
> and the new computed high/batch differs, so if everything is equal, why do we want
> to call it anyways?
My reasoning is that initially we don't have guarantee that
zone->pageset_high/batch matches the respective pcp->high/batch. So we could
detect no change in the zone values and return, but leave the pcp value
incoherent. But now I think it could be achieved also in a simpler way, so I'll try.
next prev parent reply other threads:[~2020-09-18 12:02 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
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 [this message]
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
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