Base page PMD faulting is meant to batch handle NUMA hinting faults from
PTEs. However, even is no PTE faults would ever be handled within a
range the kernel still traps PMD hinting faults. This patch avoids the
overhead.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-37-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
pmd = pmd_offset(pud, addr);
do {
pmd = pmd_offset(pud, addr);
do {
+ unsigned long this_pages;
+
next = pmd_addr_end(addr, end);
if (pmd_trans_huge(*pmd)) {
if (next - addr != HPAGE_PMD_SIZE)
next = pmd_addr_end(addr, end);
if (pmd_trans_huge(*pmd)) {
if (next - addr != HPAGE_PMD_SIZE)
}
if (pmd_none_or_clear_bad(pmd))
continue;
}
if (pmd_none_or_clear_bad(pmd))
continue;
- pages += change_pte_range(vma, pmd, addr, next, newprot,
+ this_pages = change_pte_range(vma, pmd, addr, next, newprot,
dirty_accountable, prot_numa, &all_same_nidpid);
dirty_accountable, prot_numa, &all_same_nidpid);
/*
* If we are changing protections for NUMA hinting faults then
/*
* If we are changing protections for NUMA hinting faults then
* node. This allows a regular PMD to be handled as one fault
* and effectively batches the taking of the PTL
*/
* 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_nidpid)
+ if (prot_numa && this_pages && all_same_nidpid)
change_pmd_protnuma(vma->vm_mm, addr, pmd);
} while (pmd++, addr = next, addr != end);
change_pmd_protnuma(vma->vm_mm, addr, pmd);
} while (pmd++, addr = next, addr != end);