diff options
| author | Johannes Weiner <hannes@cmpxchg.org> | 2011-01-13 15:47:04 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-13 17:32:44 -0800 |
| commit | cd7548ab360c462118568eebb8c6da3bc303b02e (patch) | |
| tree | 44d145e6139c8753659ee773ae35810dc3d92d0b | |
| parent | b36f5b0710e9e3b92484de32920fddcb17278664 (diff) | |
thp: mprotect: transparent huge page support
Natively handle huge pmds when changing page tables on behalf of
mprotect().
I left out update_mmu_cache() because we do not need it on x86 anyway but
more importantly the interface works on ptes, not pmds.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/huge_mm.h | 2 | ||||
| -rw-r--r-- | mm/huge_memory.c | 27 | ||||
| -rw-r--r-- | mm/mprotect.c | 8 |
3 files changed, 36 insertions, 1 deletions
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 25125fb6acf..c590b08c6fa 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -22,6 +22,8 @@ extern int zap_huge_pmd(struct mmu_gather *tlb, extern int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, unsigned char *vec); +extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, + unsigned long addr, pgprot_t newprot); enum transparent_hugepage_flag { TRANSPARENT_HUGEPAGE_FLAG, diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 37e89a32a0b..7b55fe0e998 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -948,6 +948,33 @@ int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, return ret; } +int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, + unsigned long addr, pgprot_t newprot) +{ + struct mm_struct *mm = vma->vm_mm; + int ret = 0; + + spin_lock(&mm->page_table_lock); + if (likely(pmd_trans_huge(*pmd))) { + if (unlikely(pmd_trans_splitting(*pmd))) { + spin_unlock(&mm->page_table_lock); + wait_split_huge_page(vma->anon_vma, pmd); + } else { + pmd_t entry; + + entry = pmdp_get_and_clear(mm, addr, pmd); + entry = pmd_modify(entry, newprot); + set_pmd_at(mm, addr, pmd, entry); + spin_unlock(&vma->vm_mm->page_table_lock); + flush_tlb_range(vma, addr, addr + HPAGE_PMD_SIZE); + ret = 1; + } + } else + spin_unlock(&vma->vm_mm->page_table_lock); + + return ret; +} + pmd_t *page_check_address_pmd(struct page *page, struct mm_struct *mm, unsigned long address, diff --git a/mm/mprotect.c b/mm/mprotect.c index 9402080d0d4..5a688a2756b 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -88,7 +88,13 @@ static inline void change_pmd_range(struct vm_area_struct *vma, pud_t *pud, pmd = pmd_offset(pud, addr); do { next = pmd_addr_end(addr, end); - split_huge_page_pmd(vma->vm_mm, pmd); + if (pmd_trans_huge(*pmd)) { + if (next - addr != HPAGE_PMD_SIZE) + split_huge_page_pmd(vma->vm_mm, pmd); + else if (change_huge_pmd(vma, pmd, addr, newprot)) + continue; + /* fall through */ + } if (pmd_none_or_clear_bad(pmd)) continue; change_pte_range(vma->vm_mm, pmd, addr, next, newprot, |