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mm/hotplug: optimize clear_hwpoisoned_pages() 

In hot remove, we try to clear poisoned pages, but a small optimization to
check if num_poisoned_pages is 0 helps remove the iteration through
nr_pages.

[akpm@linux-foundation.org: tweak comment text]
Link: http://lkml.kernel.org/r/20181102120001.4526-1-bsingharora@gmail.com
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Balbir Singh 2018-12-28 00:33:24 -08:00 committed by Linus Torvalds
parent c8f61cfc87
commit 5eb570a8d9
1 changed files with 9 additions and 0 deletions
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9
mm/sparse.c
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@ -740,6 +740,15 @@ static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
if (!memmap)
return;
/*
* A further optimization is to have per section refcounted
* num_poisoned_pages. But that would need more space per memmap, so
* for now just do a quick global check to speed up this routine in the
* absence of bad pages.
*/
if (atomic_long_read(&num_poisoned_pages) == 0)
return;
for (i = 0; i < nr_pages; i++) {
if (PageHWPoison(&memmap[i])) {
atomic_long_sub(1, &num_poisoned_pages);