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| author | Mel Gorman <mgorman@suse.de> | 2015-02-12 14:58:44 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-12 18:54:08 -0800 |
| commit | 10c1045f28e86ac90589a188f0be2d7a4347efdf (patch) | |
| tree | 1bb321876125ca1afb061ada97462fb6bb23fc2c | |
| parent | c0e7cad9f2390087b53e26e7b98958d8793ee02d (diff) | |
| download | linux-10c1045f28e86ac90589a188f0be2d7a4347efdf.tar.gz linux-10c1045f28e86ac90589a188f0be2d7a4347efdf.tar.bz2 linux-10c1045f28e86ac90589a188f0be2d7a4347efdf.zip | |
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 <mgorman@suse.de>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/huge_memory.c | 14 | ||||
| -rw-r--r-- | mm/mprotect.c | 4 |
2 files changed, 12 insertions, 6 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 8e07342b52c0..fc00c8cb5a82 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1493,12 +1493,14 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, return 0; } - ret = 1; - entry = pmdp_get_and_clear_notify(mm, addr, pmd); - entry = pmd_modify(entry, newprot); - ret = HPAGE_PMD_NR; - set_pmd_at(mm, addr, pmd, entry); - BUG_ON(pmd_write(entry)); + if (!prot_numa || !pmd_protnone(*pmd)) { + ret = 1; + entry = pmdp_get_and_clear_notify(mm, addr, pmd); + entry = pmd_modify(entry, newprot); + ret = HPAGE_PMD_NR; + set_pmd_at(mm, addr, pmd, entry); + BUG_ON(pmd_write(entry)); + } spin_unlock(ptl); } diff --git a/mm/mprotect.c b/mm/mprotect.c index dd599fc235c2..44727811bf4c 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -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); |