The patch titled
Subject: mm: fix rss count leakage during migration
has been removed from the -mm tree. Its filename was
mm-fix-rss-count-leakage-during-migration.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
Subject: mm: fix rss count leakage during migration
Memory migration fills a pte with a migration entry and it doesn't update
the rss counters. Then it replaces the migration entry with the new page
(or the old one if migration failed). But between these two passes this
pte can be unmaped, or a task can fork a child and it will get a copy of
this migration entry. Nobody accounts for this in the rss counters.
This patch properly adjust rss counters for migration entries in
zap_pte_range() and copy_one_pte(). Thus we avoid extra atomic operations
on the migration fast-path.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 37 ++++++++++++++++++++++++++++---------
1 file changed, 28 insertions(+), 9 deletions(-)
diff -puN mm/memory.c~mm-fix-rss-count-leakage-during-migration mm/memory.c
--- a/mm/memory.c~mm-fix-rss-count-leakage-during-migration
+++ a/mm/memory.c
@@ -878,15 +878,24 @@ copy_one_pte(struct mm_struct *dst_mm, s
}
if (likely(!non_swap_entry(entry)))
rss[MM_SWAPENTS]++;
- else if (is_write_migration_entry(entry) &&
- is_cow_mapping(vm_flags)) {
- /*
- * COW mappings require pages in both parent
- * and child to be set to read.
- */
- make_migration_entry_read(&entry);
- pte = swp_entry_to_pte(entry);
- set_pte_at(src_mm, addr, src_pte, pte);
+ else if (is_migration_entry(entry)) {
+ page = migration_entry_to_page(entry);
+
+ if (PageAnon(page))
+ rss[MM_ANONPAGES]++;
+ else
+ rss[MM_FILEPAGES]++;
+
+ if (is_write_migration_entry(entry) &&
+ is_cow_mapping(vm_flags)) {
+ /*
+ * COW mappings require pages in both
+ * parent and child to be set to read.
+ */
+ make_migration_entry_read(&entry);
+ pte = swp_entry_to_pte(entry);
+ set_pte_at(src_mm, addr, src_pte, pte);
+ }
}
}
goto out_set_pte;
@@ -1191,6 +1200,16 @@ again:
if (!non_swap_entry(entry))
rss[MM_SWAPENTS]--;
+ else if (is_migration_entry(entry)) {
+ struct page *page;
+
+ page = migration_entry_to_page(entry);
+
+ if (PageAnon(page))
+ rss[MM_ANONPAGES]--;
+ else
+ rss[MM_FILEPAGES]--;
+ }
if (unlikely(!free_swap_and_cache(entry)))
print_bad_pte(vma, addr, ptent, NULL);
}
_
Patches currently in -mm which might be from khlebnikov@xxxxxxxxxx are
origin.patch
linux-next.patch
mm-add-rss-counters-consistency-check.patch
mm-postpone-migrated-page-mapping-reset.patch
mm-make-get_mm_counter-static-inline.patch
mm-fix-page-faults-detection-in-swap-token-logic.patch
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