diff options
author | Mel Gorman <mgorman@suse.de> | 2012-11-15 05:24:32 +0400 |
---|---|---|
committer | Mel Gorman <mgorman@suse.de> | 2012-12-11 18:42:49 +0400 |
commit | 9532fec118d485ea37ab6e3ea372d68cd8b4cd0d (patch) | |
tree | 5076f3da1ff244df554e99b8701749423a6b92ad /mm/mprotect.c | |
parent | 5606e3877ad8baea42f3a71ebde0a03622bbb551 (diff) | |
download | linux-9532fec118d485ea37ab6e3ea372d68cd8b4cd0d.tar.xz |
mm: numa: Migrate pages handled during a pmd_numa hinting fault
To say that the PMD handling code was incorrectly transferred from autonuma
is an understatement. The intention was to handle a PMDs worth of pages
in the same fault and effectively batch the taking of the PTL and page
migration. The copied version instead has the impact of clearing a number
of pte_numa PTE entries and whether any page migration takes place depends
on racing. This just happens to work in some cases.
This patch handles pte_numa faults in batch when a pmd_numa fault is
handled. The pages are migrated if they are currently misplaced.
Essentially this is making an assumption that NUMA locality is
on a PMD boundary but that could be addressed by only setting
pmd_numa if all the pages within that PMD are on the same node
if necessary.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Diffstat (limited to 'mm/mprotect.c')
-rw-r--r-- | mm/mprotect.c | 25 |
1 files changed, 20 insertions, 5 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c index 7ef6ae964e8f..dce6fb48edc4 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -37,12 +37,14 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, pgprot_t newprot, - int dirty_accountable, int prot_numa) + int dirty_accountable, int prot_numa, bool *ret_all_same_node) { struct mm_struct *mm = vma->vm_mm; pte_t *pte, oldpte; spinlock_t *ptl; unsigned long pages = 0; + bool all_same_node = true; + int last_nid = -1; pte = pte_offset_map_lock(mm, pmd, addr, &ptl); arch_enter_lazy_mmu_mode(); @@ -61,6 +63,12 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, page = vm_normal_page(vma, addr, oldpte); if (page) { + int this_nid = page_to_nid(page); + if (last_nid == -1) + last_nid = this_nid; + if (last_nid != this_nid) + all_same_node = false; + /* only check non-shared pages */ if (!pte_numa(oldpte) && page_mapcount(page) == 1) { @@ -81,7 +89,6 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, if (updated) pages++; - ptep_modify_prot_commit(mm, addr, pte, ptent); } else if (IS_ENABLED(CONFIG_MIGRATION) && !pte_file(oldpte)) { swp_entry_t entry = pte_to_swp_entry(oldpte); @@ -101,6 +108,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, arch_leave_lazy_mmu_mode(); pte_unmap_unlock(pte - 1, ptl); + *ret_all_same_node = all_same_node; return pages; } @@ -127,6 +135,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, pud_t * pmd_t *pmd; unsigned long next; unsigned long pages = 0; + bool all_same_node; pmd = pmd_offset(pud, addr); do { @@ -143,9 +152,15 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, pud_t * if (pmd_none_or_clear_bad(pmd)) continue; pages += change_pte_range(vma, pmd, addr, next, newprot, - dirty_accountable, prot_numa); - - if (prot_numa) + dirty_accountable, prot_numa, &all_same_node); + + /* + * If we are changing protections for NUMA hinting faults then + * set pmd_numa if the examined pages were all on the same + * node. This allows a regular PMD to be handled as one fault + * and effectively batches the taking of the PTL + */ + if (prot_numa && all_same_node) change_pmd_protnuma(vma->vm_mm, addr, pmd); } while (pmd++, addr = next, addr != end); |