Although the zero huge page is being shared across various processes, each mapping needs to update its mm_struct's MM_ANONPAGES stat by HPAGE_PMD_NR to be consistent. This just updates the stats in set_huge_zero_page() after the mapping gets created and in zap_huge_pmd() when mapping gets destroyed. Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Zi Yan <ziy@xxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> --- This applies on v5.13-rc2. Changes in V1: - Updated MM_ANONPAGES stat in zap_huge_pmd() - Updated the commit message Changes in RFC: https://lore.kernel.org/linux-mm/1620890438-9127-1-git-send-email-anshuman.khandual@xxxxxxx/ mm/huge_memory.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 63ed6b25deaa..306d0a41bf75 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -706,6 +706,7 @@ static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, if (pgtable) pgtable_trans_huge_deposit(mm, pmd, pgtable); set_pmd_at(mm, haddr, pmd, entry); + add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); mm_inc_nr_ptes(mm); } @@ -1678,6 +1679,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); } else if (is_huge_zero_pmd(orig_pmd)) { zap_deposited_table(tlb->mm, pmd); + add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); spin_unlock(ptl); tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE); } else { -- 2.20.1
