diff options
| author | David Miller <davem@davemloft.net> | 2012-10-08 16:34:26 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:23:06 +0900 |
| commit | f5c8ad47284ca01dafc37da5a72bb9644174d387 (patch) | |
| tree | 9d05ff565ad5e3b90933cacad012ad9724a8a83e /mm | |
| parent | b113da65785d5f3f9ff1451ec0fe43d6d76da25b (diff) | |
mm: thp: Use more portable PMD clearing sequenece in zap_huge_pmd().
Invalidation sequences are handled in various ways on various
architectures.
One way, which sparc64 uses, is to let the set_*_at() functions accumulate
pending flushes into a per-cpu array. Then the flush_tlb_range() et al.
calls process the pending TLB flushes.
In this regime, the __tlb_remove_*tlb_entry() implementations are
essentially NOPs.
The canonical PTE zap in mm/memory.c is:
ptent = ptep_get_and_clear_full(mm, addr, pte,
tlb->fullmm);
tlb_remove_tlb_entry(tlb, pte, addr);
With a subsequent tlb_flush_mmu() if needed.
Mirror this in the THP PMD zapping using:
orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
page = pmd_page(orig_pmd);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
And we properly accomodate TLB flush mechanims like the one described
above.
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/huge_memory.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 68a3c93036f6..a863af26c79c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1024,9 +1024,10 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, if (__pmd_trans_huge_lock(pmd, vma) == 1) { struct page *page; pgtable_t pgtable; + pmd_t orig_pmd; pgtable = pgtable_trans_huge_withdraw(tlb->mm); - page = pmd_page(*pmd); - pmd_clear(pmd); + orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); + page = pmd_page(orig_pmd); tlb_remove_pmd_tlb_entry(tlb, pmd, addr); page_remove_rmap(page); VM_BUG_ON(page_mapcount(page) < 0); |