diff options
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cb9b3e847dac..8e791a3db6b6 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1471,7 +1471,7 @@ out: * - HPAGE_PMD_NR is protections changed and TLB flush necessary */ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, - unsigned long addr, pgprot_t newprot) + unsigned long addr, pgprot_t newprot, int prot_numa) { struct mm_struct *mm = vma->vm_mm; spinlock_t *ptl; @@ -1479,6 +1479,17 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { pmd_t entry; + + /* + * Avoid trapping faults against the zero page. The read-only + * data is likely to be read-cached on the local CPU and + * local/remote hits to the zero page are not interesting. + */ + if (prot_numa && is_huge_zero_pmd(*pmd)) { + spin_unlock(ptl); + return 0; + } + ret = 1; entry = pmdp_get_and_clear_notify(mm, addr, pmd); entry = pmd_modify(entry, newprot); |