The patch titled
Subject: mm/hotplug: optimize clear_hwpoisoned_pages()
has been added to the -mm tree. Its filename is
mm-hotplug-optimize-clear_hwpoisoned_pages.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hotplug-optimize-clear_hwpoisoned_pages.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hotplug-optimize-clear_hwpoisoned_pages.patch
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------------------------------------------------------
From: Balbir Singh <bsingharora@xxxxxxxxx>
Subject: 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.
Link: http://lkml.kernel.org/r/20181102120001.4526-1-bsingharora@xxxxxxxxx
Signed-off-by: Balbir Singh <bsingharora@xxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Naoya Horiguchi <nao.horiguchi@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/sparse.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/mm/sparse.c~mm-hotplug-optimize-clear_hwpoisoned_pages
+++ a/mm/sparse.c
@@ -724,6 +724,16 @@ static void clear_hwpoisoned_pages(struc
if (!memmap)
return;
+ /*
+ * A further optimization is to have per section
+ * ref counted num_poisoned_pages, but that is going
+ * to need more space per memmap, for now just do
+ * a quick global check, this should 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);
_
Patches currently in -mm which might be from bsingharora@xxxxxxxxx are
mm-hotplug-optimize-clear_hwpoisoned_pages.patch
