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authorMel Gorman <mgorman@suse.de>2013-10-07 14:28:48 +0400
committerIngo Molnar <mingo@kernel.org>2013-10-09 14:39:48 +0400
commite920e14ca29b0b2a981cfc90e4e20edd6f078d19 (patch)
treee8f8530aaddb664bc811289aa0e096890a40dd2e /mm/mprotect.c
parentafcae2655b0ab67e65f161b1bb214efcfa1db415 (diff)
downloadlinux-e920e14ca29b0b2a981cfc90e4e20edd6f078d19.tar.xz
mm: Do not flush TLB during protection change if !pte_present && !migration_entry
NUMA PTE scanning is expensive both in terms of the scanning itself and the TLB flush if there are any updates. Currently non-present PTEs are accounted for as an update and incurring a TLB flush where it is only necessary for anonymous migration entries. This patch addresses the problem and should reduce TLB flushes. Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-11-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/mprotect.c')
-rw-r--r--mm/mprotect.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 2bbb648ea73f..7bdbd4b0f6d9 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -101,8 +101,9 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
make_migration_entry_read(&entry);
set_pte_at(mm, addr, pte,
swp_entry_to_pte(entry));
+
+ pages++;
}
- pages++;
}
} while (pte++, addr += PAGE_SIZE, addr != end);
arch_leave_lazy_mmu_mode();