On 2015년 08월 03일 21:27, Minchan Kim wrote:
> Hello,
>
> On Mon, Aug 03, 2015 at 07:18:27PM +0900, Jaewon Kim wrote:
>> reclaim_clean_pages_from_list() decreases NR_ISOLATED_FILE by returned
>> value from shrink_page_list(). But mlocked pages in the isolated
>> clean_pages page list would be removed from the list but not counted as
>> nr_reclaimed. Fix this miscounting by returning the number of mlocked
>> pages and count it.
>
> If there are pages not able to reclaim, VM try to migrate it and
> have to handle the stat in migrate_pages.
> If migrate_pages fails again, putback-fiends should handle it.
>
> Is there anyting I am missing now?
>
> Thanks.
>
Hello
Only pages in cc->migratepages will be handled by migrate_pages or
putback_movable_pages, and NR_ISOLATED_FILE will be counted properly.
However mlocked pages will not be put back into cc->migratepages,
and also not be counted in NR_ISOLATED_FILE because putback_lru_page
in shrink_page_list does not increase NR_ISOLATED_FILE.
The current reclaim_clean_pages_from_list assumes that shrink_page_list
returns number of pages removed from the candidate list.
i.e)
isolate_migratepages_range : NR_ISOLATED_FILE += 10
reclaim_clean_pages_from_list : NR_ISOLATED_FILE -= 5 (1 mlocked page)
migrate_pages : NR_ISOLATED_FILE -=4
=> NR_ISOLATED_FILE increased by 1
Thank you.
>>
>> Signed-off-by: Jaewon Kim <jaewon31.kim@xxxxxxxxxxx>
>> ---
>> mm/vmscan.c | 10 ++++++++--
>> 1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index 5e8eadd..5837695 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -849,6 +849,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
>> unsigned long *ret_nr_congested,
>> unsigned long *ret_nr_writeback,
>> unsigned long *ret_nr_immediate,
>> + unsigned long *ret_nr_mlocked,
>> bool force_reclaim)
>> {
>> LIST_HEAD(ret_pages);
>> @@ -1158,6 +1159,7 @@ cull_mlocked:
>> try_to_free_swap(page);
>> unlock_page(page);
>> putback_lru_page(page);
>> + (*ret_nr_mlocked)++;
>> continue;
>>
>> activate_locked:
>> @@ -1197,6 +1199,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
>> .may_unmap = 1,
>> };
>> unsigned long ret, dummy1, dummy2, dummy3, dummy4, dummy5;
>> + unsigned long nr_mlocked = 0;
>> struct page *page, *next;
>> LIST_HEAD(clean_pages);
>>
>> @@ -1210,8 +1213,10 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
>>
>> ret = shrink_page_list(&clean_pages, zone, &sc,
>> TTU_UNMAP|TTU_IGNORE_ACCESS,
>> - &dummy1, &dummy2, &dummy3, &dummy4, &dummy5, true);
>> + &dummy1, &dummy2, &dummy3, &dummy4, &dummy5,
>> + &nr_mlocked, true);
>> list_splice(&clean_pages, page_list);
>> + ret += nr_mlocked;
>> mod_zone_page_state(zone, NR_ISOLATED_FILE, -ret);
>> return ret;
>> }
>> @@ -1523,6 +1528,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
>> unsigned long nr_unqueued_dirty = 0;
>> unsigned long nr_writeback = 0;
>> unsigned long nr_immediate = 0;
>> + unsigned long nr_mlocked = 0;
>> isolate_mode_t isolate_mode = 0;
>> int file = is_file_lru(lru);
>> struct zone *zone = lruvec_zone(lruvec);
>> @@ -1565,7 +1571,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
>>
>> nr_reclaimed = shrink_page_list(&page_list, zone, sc, TTU_UNMAP,
>> &nr_dirty, &nr_unqueued_dirty, &nr_congested,
>> - &nr_writeback, &nr_immediate,
>> + &nr_writeback, &nr_immediate, &nr_mlocked,
>> false);
>>
>> spin_lock_irq(&zone->lru_lock);
>> --
>> 1.9.1
>>
>
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