On 2015년 08월 04일 00:33, Minchan Kim wrote: > On Mon, Aug 03, 2015 at 11:55:46PM +0900, Jaewon Kim wrote: >> >> >> 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 > > Thanks for the clarity. > > I think the problem is shrink_page_list is awkard. It put back to > unevictable pages instantly instead of passing it to caller while > it relies on caller for non-reclaimed-non-unevictable page's putback. > > I think we can make it consistent so that shrink_page_list could > return non-reclaimed pages via page_list and caller can handle it. > As a bonus, it could try to migrate mlocked pages without retrial. > >> >> Thank you. To make clear do you mean changing shrink_page_list like this rather than previous my suggestion? @@ -1157,7 +1157,7 @@ cull_mlocked: if (PageSwapCache(page)) try_to_free_swap(page); unlock_page(page); - putback_lru_page(page); + list_add(&page->lru, &ret_pages); continue; 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 >>>> >>> > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>