On 04/26/2016 02:55 AM, Joonsoo Kim wrote:
On Mon, Apr 25, 2016 at 03:35:50PM +0200, Vlastimil Babka wrote:
@@ -846,9 +845,11 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
spin_unlock_irqrestore(&zone->lru_lock, flags);
locked = false;
}
- putback_movable_pages(migratelist);
- nr_isolated = 0;
+ acct_isolated(zone, cc);
+ putback_movable_pages(&cc->migratepages);
+ cc->nr_migratepages = 0;
cc->last_migrated_pfn = 0;
+ nr_isolated = 0;
Is it better to use separate list and merge it cc->migratepages when
finishing instead of using cc->migratepages directly? If
isolate_migratepages() try to isolate more than one page block and keep
isolated page on previous pageblock, this putback all will invalidate
all the previous work. It would be beyond of the scope of this
function. Now, isolate_migratepages() try to isolate the page in one
pageblock so this code is safe. But, I think that removing such
dependency will be helpful in the future. I'm not strongly insisting it
so if you think it's not useful thing, please ignore this comment.
migratelist was merely a reference to cc->migratepages, so it wouldn't prevent
the situation you are suggesting. A truly separate list would need to be
appended to cc->migratepages when leaving isolate_migratepages_block() and
there's no need to do that right now.
BTW, can you check patch 1/3? Thanks!
Vlastimil
Thanks.
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