From: Vlastimil Babka <vbabka@suse.cz>
To: Hugh Dickins <hughd@google.com>, Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: mmotm woes, mainly compaction
Date: Mon, 18 Apr 2016 15:14:13 -0400 [thread overview]
Message-ID: <57153205.4050406@suse.cz> (raw)
In-Reply-To: <571026CA.6000708@suse.cz>
On 04/14/2016 07:24 PM, Vlastimil Babka wrote:
>> > @@ -1459,8 +1459,8 @@ static enum compact_result compact_zone(
>> > zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn;
>> > }
>> >
>> > - if (cc->migrate_pfn == start_pfn)
>> > - cc->whole_zone = true;
>> > + cc->whole_zone = cc->migrate_pfn == start_pfn &&
>> > + cc->free_pfn == pageblock_start_pfn(end_pfn - 1);
>> >
>> > cc->last_migrated_pfn = 0;
> This would be for Michal, but I agree.
So there's an alternative here that wouldn't have the danger of missing
cc->whole_zone multiple time due to races. When resetting either one
scanner to zone boundary, reset the other as well (and set
cc->whole_zone). I think the situations, where not doing that have any
(performance) advantage, are rare.
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WARNING: multiple messages have this Message-ID (diff)
From: Vlastimil Babka <vbabka@suse.cz>
To: Hugh Dickins <hughd@google.com>, Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: mmotm woes, mainly compaction
Date: Mon, 18 Apr 2016 15:14:13 -0400 [thread overview]
Message-ID: <57153205.4050406@suse.cz> (raw)
In-Reply-To: <571026CA.6000708@suse.cz>
On 04/14/2016 07:24 PM, Vlastimil Babka wrote:
>> > @@ -1459,8 +1459,8 @@ static enum compact_result compact_zone(
>> > zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn;
>> > }
>> >
>> > - if (cc->migrate_pfn == start_pfn)
>> > - cc->whole_zone = true;
>> > + cc->whole_zone = cc->migrate_pfn == start_pfn &&
>> > + cc->free_pfn == pageblock_start_pfn(end_pfn - 1);
>> >
>> > cc->last_migrated_pfn = 0;
> This would be for Michal, but I agree.
So there's an alternative here that wouldn't have the danger of missing
cc->whole_zone multiple time due to races. When resetting either one
scanner to zone boundary, reset the other as well (and set
cc->whole_zone). I think the situations, where not doing that have any
(performance) advantage, are rare.
next prev parent reply other threads:[~2016-04-18 19:14 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-12 7:18 mmotm woes, mainly compaction Hugh Dickins
2016-04-12 7:18 ` Hugh Dickins
2016-04-12 8:03 ` Vlastimil Babka
2016-04-12 8:03 ` Vlastimil Babka
2016-04-12 9:03 ` Vlastimil Babka
2016-04-12 9:03 ` Vlastimil Babka
2016-04-12 9:14 ` Vlastimil Babka
2016-04-12 9:14 ` Vlastimil Babka
2016-04-12 9:31 ` Vlastimil Babka
2016-04-12 9:31 ` Vlastimil Babka
2016-04-12 9:38 ` Vlastimil Babka
2016-04-12 9:38 ` Vlastimil Babka
2016-04-12 12:10 ` Michal Hocko
2016-04-12 12:10 ` Michal Hocko
2016-04-12 14:51 ` Michal Hocko
2016-04-12 14:51 ` Michal Hocko
2016-04-14 20:15 ` Hugh Dickins
2016-04-14 20:15 ` Hugh Dickins
2016-04-14 23:24 ` Vlastimil Babka
2016-04-14 23:24 ` Vlastimil Babka
2016-04-15 1:00 ` Hugh Dickins
2016-04-15 1:00 ` Hugh Dickins
2016-04-18 19:14 ` Vlastimil Babka [this message]
2016-04-18 19:14 ` Vlastimil Babka
2016-04-15 8:42 ` Michal Hocko
2016-04-15 8:42 ` Michal Hocko
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