Messages in this thread | | | Subject | Re: [RFC PATCH] mm/page_alloc: fix counting of free pages after take off from buddy | From | Ding Hui <> | Date | Fri, 30 Apr 2021 17:43:40 +0800 |
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On 2021/4/28 22:54, David Hildenbrand wrote: > On 21.04.21 04:04, Ding Hui wrote: >> Recently we found there is a lot MemFree left in /proc/meminfo after >> do a lot of pages soft offline. >> >> I think it's incorrect since NR_FREE_PAGES should not contain HWPoison >> pages. >> After take_page_off_buddy, the page is no longer belong to buddy >> allocator, and will not be used any more, but we maybe missed accounting >> NR_FREE_PAGES in this situation. >> >> Signed-off-by: Ding Hui <dinghui@sangfor.com.cn> >> --- >> mm/page_alloc.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index cfc72873961d..8d65b62784d8 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -8947,6 +8947,7 @@ bool take_page_off_buddy(struct page *page) >> del_page_from_free_list(page_head, zone, page_order); >> break_down_buddy_pages(zone, page_head, page, 0, >> page_order, migratetype); >> + __mod_zone_page_state(zone, NR_FREE_PAGES, -1); >> ret = true; >> break; >> } >> > > Should this use __mod_zone_freepage_state() instead? >
Yes, you're right. I'll use it in v2.
-- Thanks, - Ding Hui
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