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authorMichal Hocko <mhocko@suse.com>2017-11-15 17:33:22 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-15 18:21:02 -0800
commitd7b236e10cedd95373a79fd53b7e9c105bea4f08 (patch)
tree8deeb1385ace737b7c56591fc0e357e661302908 /mm/page_alloc.c
parent4c578dce58038a5b3cb7ffc77a5f62ef2c5d0856 (diff)
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mm: drop migrate type checks from has_unmovable_pages
Michael has noticed that the memory offline tries to migrate kernel code pages when doing echo 0 > /sys/devices/system/memory/memory0/online The current implementation will fail the operation after several failed page migration attempts but we shouldn't even attempt to migrate that memory and fail right away because this memory is clearly not migrateable. This will become a real problem when we drop the retry loop counter resp. timeout. The real problem is in has_unmovable_pages in fact. We should fail if there are any non migrateable pages in the area. In orther to guarantee that remove the migrate type checks because MIGRATE_MOVABLE is not guaranteed to contain only migrateable pages. It is merely a heuristic. Similarly MIGRATE_CMA does guarantee that the page allocator doesn't allocate any non-migrateable pages from the block but CMA allocations themselves are unlikely to migrateable. Therefore remove both checks. [akpm@linux-foundation.org: remove unused local `mt'] Link: http://lkml.kernel.org/r/20171013120013.698-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Ran Wang <ran.wang_1@nxp.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c4
1 files changed, 0 insertions, 4 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 77e4d3c..e6d4234 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7356,7 +7356,6 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
bool skip_hwpoisoned_pages)
{
unsigned long pfn, iter, found;
- int mt;
/*
* For avoiding noise data, lru_add_drain_all() should be called
@@ -7364,9 +7363,6 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
*/
if (zone_idx(zone) == ZONE_MOVABLE)
return false;
- mt = get_pageblock_migratetype(page);
- if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
- return false;
pfn = page_to_pfn(page);
for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
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