2015-02-02 18:59 GMT+09:00 Vlastimil Babka <vbabka@xxxxxxx>:
> On 02/02/2015 08:15 AM, Joonsoo Kim wrote:
>> This is preparation step to use page allocator's anti fragmentation logic
>> in compaction. This patch just separates fallback freepage checking part
>> from fallback freepage management part. Therefore, there is no functional
>> change.
>>
>> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
>> ---
>> mm/page_alloc.c | 128 +++++++++++++++++++++++++++++++++-----------------------
>> 1 file changed, 76 insertions(+), 52 deletions(-)
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index e64b260..6cb18f8 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -1142,14 +1142,26 @@ static void change_pageblock_range(struct page *pageblock_page,
>> * as fragmentation caused by those allocations polluting movable pageblocks
>> * is worse than movable allocations stealing from unmovable and reclaimable
>> * pageblocks.
>> - *
>> - * If we claim more than half of the pageblock, change pageblock's migratetype
>> - * as well.
>> */
>> -static void try_to_steal_freepages(struct zone *zone, struct page *page,
>> - int start_type, int fallback_type)
>> +static bool can_steal_fallback(unsigned int order, int start_mt)
>> +{
>> + if (order >= pageblock_order)
>> + return true;
>> +
>> + if (order >= pageblock_order / 2 ||
>> + start_mt == MIGRATE_RECLAIMABLE ||
>> + start_mt == MIGRATE_UNMOVABLE ||
>> + page_group_by_mobility_disabled)
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> +static void steal_suitable_fallback(struct zone *zone, struct page *page,
>> + int start_type)
>
> Some comment about the function please?
Okay.
>> {
>> int current_order = page_order(page);
>> + int pages;
>>
>> /* Take ownership for orders >= pageblock_order */
>> if (current_order >= pageblock_order) {
>> @@ -1157,19 +1169,39 @@ static void try_to_steal_freepages(struct zone *zone, struct page *page,
>> return;
>> }
>>
>> - if (current_order >= pageblock_order / 2 ||
>> - start_type == MIGRATE_RECLAIMABLE ||
>> - start_type == MIGRATE_UNMOVABLE ||
>> - page_group_by_mobility_disabled) {
>> - int pages;
>> + pages = move_freepages_block(zone, page, start_type);
>>
>> - pages = move_freepages_block(zone, page, start_type);
>> + /* Claim the whole block if over half of it is free */
>> + if (pages >= (1 << (pageblock_order-1)) ||
>> + page_group_by_mobility_disabled)
>> + set_pageblock_migratetype(page, start_type);
>> +}
>>
>> - /* Claim the whole block if over half of it is free */
>> - if (pages >= (1 << (pageblock_order-1)) ||
>> - page_group_by_mobility_disabled)
>> - set_pageblock_migratetype(page, start_type);
>> +static int find_suitable_fallback(struct free_area *area, unsigned int order,
>> + int migratetype, bool *can_steal)
>
> Same here.
Okay.
>> +{
>> + int i;
>> + int fallback_mt;
>> +
>> + if (area->nr_free == 0)
>> + return -1;
>> +
>> + *can_steal = false;
>> + for (i = 0;; i++) {
>> + fallback_mt = fallbacks[migratetype][i];
>> + if (fallback_mt == MIGRATE_RESERVE)
>> + break;
>> +
>> + if (list_empty(&area->free_list[fallback_mt]))
>> + continue;
>> +
>> + if (can_steal_fallback(order, migratetype))
>> + *can_steal = true;
>> +
>> + return i;
>
> You want to return fallback_mt, not 'i', no?
Yes. I will fix it.
Thanks.
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