diff options
| author | Kirill A. Shutemov | 2016-07-26 15:25:37 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2016-07-26 16:19:19 -0700 |
| commit | d21b9e57c74ce82ac459e2ec8ce667db9b9da8b0 (patch) | |
| tree | e35f06f7e07e8bfbc0d1a7d19a52d6ccc87116d4 | |
| parent | b5072380eb619786990cd9eab3ade05d09ccd89e (diff) | |
thp: handle file pages in split_huge_pmd()
Splitting THP PMD is simple: just unmap it as in DAX case. This way we
can avoid memory overhead on page table allocation to deposit.
It's probably a good idea to try to allocation page table with
GFP_ATOMIC in __split_huge_pmd_locked() to avoid refaulting the area,
but clearing pmd should be good enough for now.
Unlike DAX, we also remove the page from rmap and drop reference.
pmd_young() is transfered to PageReferenced().
Link: http://lkml.kernel.org/r/1466021202-61880-15-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/huge_memory.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d8ccd245947d..e6725c5c5a62 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2987,10 +2987,18 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, count_vm_event(THP_SPLIT_PMD); - if (vma_is_dax(vma)) { - pmd_t _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); + if (!vma_is_anonymous(vma)) { + _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); if (is_huge_zero_pmd(_pmd)) put_huge_zero_page(); + if (vma_is_dax(vma)) + return; + page = pmd_page(_pmd); + if (!PageReferenced(page) && pmd_young(_pmd)) + SetPageReferenced(page); + page_remove_rmap(page, true); + put_page(page); + add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR); return; } else if (is_huge_zero_pmd(*pmd)) { return __split_huge_zero_page_pmd(vma, haddr, pmd); |