The patch titled
thp-tail-page-refcounting-fix-6
has been added to the -mm tree. Its filename is
thp-tail-page-refcounting-fix-6.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: thp-tail-page-refcounting-fix-6
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Michel Lespinasse <walken@xxxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 2 +-
mm/internal.h | 5 +++++
mm/swap.c | 12 +++++++++---
3 files changed, 15 insertions(+), 4 deletions(-)
diff -puN include/linux/mm.h~thp-tail-page-refcounting-fix-6 include/linux/mm.h
--- a/include/linux/mm.h~thp-tail-page-refcounting-fix-6
+++ a/include/linux/mm.h
@@ -377,7 +377,7 @@ static inline int page_count(struct page
return atomic_read(&compound_head(page)->_count);
}
-extern int __get_page_tail(struct page *page);
+extern bool __get_page_tail(struct page *page);
static inline void get_page(struct page *page)
{
diff -puN mm/internal.h~thp-tail-page-refcounting-fix-6 mm/internal.h
--- a/mm/internal.h~thp-tail-page-refcounting-fix-6
+++ a/mm/internal.h
@@ -59,6 +59,11 @@ static inline void __get_page_tail_foll(
atomic_inc(&page->_mapcount);
}
+/*
+ * This is meant to be called as the FOLL_GET operation of
+ * follow_page() and it must be called while holding the proper PT
+ * lock while the pte (or pmd_trans_huge) is still mapping the page.
+ */
static inline void get_page_foll(struct page *page)
{
if (unlikely(PageTail(page)))
diff -puN mm/swap.c~thp-tail-page-refcounting-fix-6 mm/swap.c
--- a/mm/swap.c~thp-tail-page-refcounting-fix-6
+++ a/mm/swap.c
@@ -79,6 +79,7 @@ static void put_compound_page(struct pag
if (unlikely(PageTail(page))) {
/* __split_huge_page_refcount can run under us */
struct page *page_head = compound_trans_head(page);
+
if (likely(page != page_head &&
get_page_unless_zero(page_head))) {
unsigned long flags;
@@ -143,7 +144,11 @@ void put_page(struct page *page)
}
EXPORT_SYMBOL(put_page);
-int __get_page_tail(struct page *page)
+/*
+ * This function is exported but must not be called by anything other
+ * than get_page(). It implements the slow path of get_page().
+ */
+bool __get_page_tail(struct page *page)
{
/*
* This takes care of get_page() if run on a tail page
@@ -154,8 +159,9 @@ int __get_page_tail(struct page *page)
* split_huge_page().
*/
unsigned long flags;
- int got = 0;
+ bool got = false;
struct page *page_head = compound_trans_head(page);
+
if (likely(page != page_head && get_page_unless_zero(page_head))) {
/*
* page_head wasn't a dangling pointer but it
@@ -167,7 +173,7 @@ int __get_page_tail(struct page *page)
/* here __split_huge_page_refcount won't run anymore */
if (likely(PageTail(page))) {
__get_page_tail_foll(page, false);
- got = 1;
+ got = true;
}
compound_unlock_irqrestore(page_head, flags);
if (unlikely(!got))
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
mm-compaction-trivial-clean-up-in-acct_isolated.patch
mm-change-isolate-mode-from-define-to-bitwise-type.patch
mm-compaction-make-isolate_lru_page-filter-aware.patch
mm-compaction-make-isolate_lru_page-filter-aware-fix.patch
mm-zone_reclaim-make-isolate_lru_page-filter-aware.patch
mm-zone_reclaim-make-isolate_lru_page-filter-aware-fix.patch
mm-migration-clean-up-unmap_and_move.patch
mremap-check-for-overflow-using-deltas.patch
mremap-avoid-sending-one-ipi-per-page.patch
thp-mremap-support-and-tlb-optimization.patch
thp-mremap-support-and-tlb-optimization-fix.patch
thp-mremap-support-and-tlb-optimization-fix-fix.patch
thp-mremap-support-and-tlb-optimization-fix-fix-fix.patch
thp-tail-page-refcounting-fix-5.patch
thp-tail-page-refcounting-fix-6.patch
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