The patch titled
Subject: mm,compaction: fix isolate_migratepages_block() for THP=n
has been added to the -mm tree. Its filename is
compaction-fix-isolate_migratepages_block-for-thp=n.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/compaction-fix-isolate_migratepages_block-for-thp%3Dn.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/compaction-fix-isolate_migratepages_block-for-thp%3Dn.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm,compaction: fix isolate_migratepages_block() for THP=n
PageTrans* helpers are always false if THP is disabled at compile-time.
It means isolate_migratepages_block() will fail to detect hugetlb pages in
this case.
Let's use PageCompound() instead. With a small tweak to how we calculate
next low_pfn it will make isolate_migratepages_block() ready to see tail
pages.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
diff -puN mm/compaction.c~compaction-fix-isolate_migratepages_block-for-thp=n mm/compaction.c
--- a/mm/compaction.c~compaction-fix-isolate_migratepages_block-for-thp=n
+++ a/mm/compaction.c
@@ -732,18 +732,18 @@ isolate_migratepages_block(struct compac
* splitting and collapsing (collapsing has already happened
* if PageLRU is set) but the lock is not necessarily taken
* here and it is wasteful to take it just to check transhuge.
- * Check TransHuge without lock and skip the whole pageblock if
- * it's either a transhuge or hugetlbfs page, as calling
+ * Check PageCompound without lock and skip the whole pageblock
+ * if it's either a transhuge or hugetlbfs page, as calling
* compound_order() without preventing THP from splitting the
* page underneath us may return surprising results.
*/
- if (PageTransHuge(page)) {
- if (!locked)
- low_pfn = ALIGN(low_pfn + 1,
- pageblock_nr_pages) - 1;
+ if (PageCompound(page)) {
+ int nr;
+ if (locked)
+ nr = 1 << compound_order(page);
else
- low_pfn += (1 << compound_order(page)) - 1;
-
+ nr = pageblock_nr_pages;
+ low_pfn = ALIGN(low_pfn + 1, nr) - 1;
continue;
}
@@ -763,11 +763,12 @@ isolate_migratepages_block(struct compac
if (!locked)
break;
- /* Recheck PageLRU and PageTransHuge under lock */
+ /* Recheck PageLRU and PageCompound under lock */
if (!PageLRU(page))
continue;
- if (PageTransHuge(page)) {
- low_pfn += (1 << compound_order(page)) - 1;
+ if (PageCompound(page)) {
+ int nr = 1 << compound_order(page);
+ low_pfn = ALIGN(low_pfn + 1, nr) - 1;
continue;
}
}
@@ -778,7 +779,7 @@ isolate_migratepages_block(struct compac
if (__isolate_lru_page(page, isolate_mode) != 0)
continue;
- VM_BUG_ON_PAGE(PageTransCompound(page), page);
+ VM_BUG_ON_PAGE(PageCompound(page), page);
/* Successfully isolated */
del_page_from_lru_list(page, lruvec, page_lru(page));
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
mm-fix-mprotect-behaviour-on-vm_locked-vmas.patch
mm-fix-mprotect-behaviour-on-vm_locked-vmas-fix.patch
mm-new-mm-hook-framework.patch
mm-new-arch_remap-hook.patch
powerpc-mm-tracking-vdso-remap.patch
compaction-fix-isolate_migratepages_block-for-thp=n.patch
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages.patch
page-flags-define-pg_locked-behavior-on-compound-pages.patch
page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages.patch
page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch
page-flags-define-pg_swapcache-behavior-on-compound-pages.patch
page-flags-define-pg_mlocked-behavior-on-compound-pages.patch
page-flags-define-pg_uncached-behavior-on-compound-pages.patch
page-flags-define-pg_uptodate-behavior-on-compound-pages.patch
page-flags-look-on-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
include-linux-page-flagsh-rename-macros-to-avoid-collisions.patch
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