The patch titled
Subject: mm/huge_memory: check pmd_present first in is_huge_zero_pmd
has been added to the -mm mm-unstable branch. Its filename is
mm-huge_memory-check-pmd_present-first-in-is_huge_zero_pmd.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-check-pmd_present-first-in-is_huge_zero_pmd.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/huge_memory: check pmd_present first in is_huge_zero_pmd
Date: Mon, 4 Jul 2022 21:21:55 +0800
When pmd is non-present, pmd_pfn returns an insane value. So we should
check pmd_present first to avoid acquiring such insane value and also
avoid touching possible cold huge_zero_pfn cache line when pmd isn't
present.
Link: https://lkml.kernel.org/r/20220704132201.14611-11-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/huge_mm.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/huge_mm.h~mm-huge_memory-check-pmd_present-first-in-is_huge_zero_pmd
+++ a/include/linux/huge_mm.h
@@ -273,7 +273,7 @@ static inline bool is_huge_zero_page(str
static inline bool is_huge_zero_pmd(pmd_t pmd)
{
- return READ_ONCE(huge_zero_pfn) == pmd_pfn(pmd) && pmd_present(pmd);
+ return pmd_present(pmd) && READ_ONCE(huge_zero_pfn) == pmd_pfn(pmd);
}
static inline bool is_huge_zero_pud(pud_t pud)
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-page_alloc-minor-clean-up-for-memmap_init_compound.patch
mm-mmapc-fix-missing-call-to-vm_unacct_memory-in-mmap_region.patch
filemap-minor-cleanup-for-filemap_write_and_wait_range.patch
mm-huge_memory-use-flush_pmd_tlb_range-in-move_huge_pmd.patch
mm-huge_memory-access-vm_page_prot-with-read_once-in-remove_migration_pmd.patch
mm-huge_memory-fix-comment-of-__pud_trans_huge_lock.patch
mm-huge_memory-use-helper-touch_pud-in-huge_pud_set_accessed.patch
mm-huge_memory-use-helper-touch_pmd-in-huge_pmd_set_accessed.patch
mm-huge_memory-rename-mmun_start-to-haddr-in-remove_migration_pmd.patch
mm-huge_memory-use-helper-function-vma_lookup-in-split_huge_pages_pid.patch
mm-huge_memory-use-helper-macro-__attr_rw.patch
mm-huge_memory-fix-comment-in-zap_huge_pud.patch
mm-huge_memory-check-pmd_present-first-in-is_huge_zero_pmd.patch
mm-huge_memory-try-to-free-subpage-in-swapcache-when-possible.patch
mm-huge_memory-minor-cleanup-for-split_huge_pages_all.patch
mm-huge_memory-fix-comment-of-page_deferred_list.patch
mm-huge_memory-correct-comment-of-prep_transhuge_page.patch
mm-huge_memory-comment-the-subtly-logic-in-__split_huge_pmd.patch
mm-huge_memory-use-helper-macro-is_err_or_null-in-split_huge_pages_pid.patch
