Commit 5eb570a8 authored by Balbir Singh's avatar Balbir Singh Committed by Linus Torvalds

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.comSigned-off-by: default avatarBalbir Singh <bsingharora@gmail.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c8f61cfc
......@@ -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);
......
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