Commit 5eb570a8 authored Dec 28, 2018 by Balbir Singh Committed by Linus Torvalds Dec 28, 2018

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>

parent c8f61cfc

mm/sparse.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -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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