mm: numa: avoid unnecessary TLB flushes when setting NUMA hinting entries

If a PTE or PMD is already marked NUMA when scanning to mark entries for
NUMA hinting then it is not necessary to update the entry and incur a TLB
flush penalty.  Avoid the avoidhead where possible.

Signed-off-by: Mel Gorman <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Kirill Shutemov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Sasha Levin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Mel Gorman 2015-02-12 14:58:44 -08:00 • committed by Linus Torvalds
commit 10c1045f28
2 changed files with 12 additions and 6 deletions

View file

@ -86,6 +86,10 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
page = vm_normal_page(vma, addr, oldpte);
if (!page || PageKsm(page))
continue;
/* Avoid TLB flush if possible */
if (pte_protnone(oldpte))
continue;
}
ptent = ptep_modify_prot_start(mm, addr, pte);