diff options
| author | Rich Wiley <rwiley@nvidia.com> | 2014-03-21 16:29:31 -0700 |
|---|---|---|
| committer | Alexander Van Brunt <avanbrunt@nvidia.com> | 2014-03-25 15:02:18 -0700 |
| commit | 475c87f9adbbc8626a05025fbb48db980449e1f4 (patch) | |
| tree | a30d99a818dfeb3531c5a08a685f5a223dc8c30c /mm | |
| parent | ea6fde84113493f627772f052fbf27d67a4a8c18 (diff) | |
mm: mprotect: prevent unneeded TLB flushes from mprotect syscall
change_protection_range will only flush the tlb if change_pte_range
reports that it has actually changed the permissions of at least
one page. This patch prevents change_pte_range from counting pages
that it doesn't actually modify.
Change-Id: I53b9b2c7a635ba1395200b9ff70f6f40a053f987
Signed-off-by: Rich Wiley <rwiley@nvidia.com>
Reviewed-on: http://git-master/r/385239
Reviewed-by: Alexander Van Brunt <avanbrunt@nvidia.com>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mprotect.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c index 6b2403a2f814..8d56d3933283 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -57,8 +57,10 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, ptent = ptep_modify_prot_start(mm, addr, pte); if (!prot_numa) { + pte_t old_ptent = ptent; ptent = pte_modify(ptent, newprot); - updated = true; + if (ptent != old_ptent) + updated = true; } else { struct page *page; |