From: Hugh Dickins hughd@google.com
stable inclusion from linux-4.19.197 commit b114408b1aa2b0957877632113009bdf5efc5da2
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[ Upstream commit a765c417d876cc635f628365ec9aa6f09470069a ]
page_vma_mapped_walk() cleanup: get THP's vma_address_end() at the start, rather than later at next_pte.
It's a little unnecessary overhead on the first call, but makes for a simpler loop in the following commit.
Link: https://lkml.kernel.org/r/4542b34d-862f-7cb4-bb22-e0df6ce830a2@google.com Signed-off-by: Hugh Dickins hughd@google.com Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Alistair Popple apopple@nvidia.com Cc: Matthew Wilcox willy@infradead.org Cc: Peter Xu peterx@redhat.com Cc: Ralph Campbell rcampbell@nvidia.com Cc: Wang Yugui wangyugui@e16-tech.com Cc: Will Deacon will@kernel.org Cc: Yang Shi shy828301@gmail.com Cc: Zi Yan ziy@nvidia.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/page_vma_mapped.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 470f19c917ad5..7239c38e99e25 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -167,6 +167,15 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) return true; }
+ /* + * Seek to next pte only makes sense for THP. + * But more important than that optimization, is to filter out + * any PageKsm page: whose page->index misleads vma_address() + * and vma_address_end() to disaster. + */ + end = PageTransCompound(page) ? + vma_address_end(page, pvmw->vma) : + pvmw->address + PAGE_SIZE; if (pvmw->pte) goto next_pte; restart: @@ -234,10 +243,6 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) if (check_pte(pvmw)) return true; next_pte: - /* Seek to next pte only makes sense for THP */ - if (!PageTransHuge(page)) - return not_found(pvmw); - end = vma_address_end(page, pvmw->vma); do { pvmw->address += PAGE_SIZE; if (pvmw->address >= end)