The patch titled
Subject: page-flags: define PG_locked behavior on compound pages
has been added to the -mm tree. Its filename is
page-flags-define-pg_locked-behavior-on-compound-pages.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/page-flags-define-pg_locked-behavior-on-compound-pages.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/page-flags-define-pg_locked-behavior-on-compound-pages.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: page-flags: define PG_locked behavior on compound pages
lock_page() must operate on the whole compound page. It doesn't make much
sense to lock part of compound page. Change code to use head page's
PG_locked, if tail page is passed.
This patch also gets rid of custom helper functions -- __set_page_locked()
and __clear_page_locked(). They are replaced with helpers generated by
__SETPAGEFLAG/__CLEARPAGEFLAG. Tail pages to these helper would trigger
VM_BUG_ON().
SLUB uses PG_locked as a bit spin locked. IIUC, tail pages should never
appear there. VM_BUG_ON() is added to make sure that this assumption is
correct.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Steve Capper <steve.capper@xxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Jerome Marchand <jmarchan@xxxxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 2 +-
include/linux/pagemap.h | 25 ++++++++-----------------
mm/filemap.c | 15 +++++++++------
mm/ksm.c | 2 +-
mm/memory-failure.c | 2 +-
mm/migrate.c | 2 +-
mm/shmem.c | 4 ++--
mm/slub.c | 2 ++
mm/swap_state.c | 4 ++--
mm/vmscan.c | 2 +-
10 files changed, 28 insertions(+), 32 deletions(-)
diff -puN include/linux/page-flags.h~page-flags-define-pg_locked-behavior-on-compound-pages include/linux/page-flags.h
--- a/include/linux/page-flags.h~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/include/linux/page-flags.h
@@ -244,7 +244,7 @@ static inline int __TestClearPage##uname
#define TESTSCFLAG_FALSE(uname) \
TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
-TESTPAGEFLAG(Locked, locked, PF_ANY)
+__PAGEFLAG(Locked, locked, PF_NO_TAIL)
PAGEFLAG(Error, error, PF_ANY) TESTCLEARFLAG(Error, error, PF_ANY)
PAGEFLAG(Referenced, referenced, PF_ANY) TESTCLEARFLAG(Referenced, referenced, PF_ANY)
__SETPAGEFLAG(Referenced, referenced, PF_ANY)
diff -puN include/linux/pagemap.h~page-flags-define-pg_locked-behavior-on-compound-pages include/linux/pagemap.h
--- a/include/linux/pagemap.h~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/include/linux/pagemap.h
@@ -426,18 +426,9 @@ extern int __lock_page_or_retry(struct p
unsigned int flags);
extern void unlock_page(struct page *page);
-static inline void __set_page_locked(struct page *page)
-{
- __set_bit(PG_locked, &page->flags);
-}
-
-static inline void __clear_page_locked(struct page *page)
-{
- __clear_bit(PG_locked, &page->flags);
-}
-
static inline int trylock_page(struct page *page)
{
+ page = compound_head(page);
return (likely(!test_and_set_bit_lock(PG_locked, &page->flags)));
}
@@ -490,9 +481,9 @@ extern int wait_on_page_bit_killable_tim
static inline int wait_on_page_locked_killable(struct page *page)
{
- if (PageLocked(page))
- return wait_on_page_bit_killable(page, PG_locked);
- return 0;
+ if (!PageLocked(page))
+ return 0;
+ return wait_on_page_bit_killable(compound_head(page), PG_locked);
}
extern wait_queue_head_t *page_waitqueue(struct page *page);
@@ -511,7 +502,7 @@ static inline void wake_up_page(struct p
static inline void wait_on_page_locked(struct page *page)
{
if (PageLocked(page))
- wait_on_page_bit(page, PG_locked);
+ wait_on_page_bit(compound_head(page), PG_locked);
}
/*
@@ -657,17 +648,17 @@ int replace_page_cache_page(struct page
/*
* Like add_to_page_cache_locked, but used to add newly allocated pages:
- * the page is new, so we can just run __set_page_locked() against it.
+ * the page is new, so we can just run __SetPageLocked() against it.
*/
static inline int add_to_page_cache(struct page *page,
struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask)
{
int error;
- __set_page_locked(page);
+ __SetPageLocked(page);
error = add_to_page_cache_locked(page, mapping, offset, gfp_mask);
if (unlikely(error))
- __clear_page_locked(page);
+ __ClearPageLocked(page);
return error;
}
diff -puN mm/filemap.c~page-flags-define-pg_locked-behavior-on-compound-pages mm/filemap.c
--- a/mm/filemap.c~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/mm/filemap.c
@@ -682,11 +682,11 @@ int add_to_page_cache_lru(struct page *p
void *shadow = NULL;
int ret;
- __set_page_locked(page);
+ __SetPageLocked(page);
ret = __add_to_page_cache_locked(page, mapping, offset,
gfp_mask, &shadow);
if (unlikely(ret))
- __clear_page_locked(page);
+ __ClearPageLocked(page);
else {
/*
* The page might have been evicted from cache only
@@ -809,6 +809,7 @@ EXPORT_SYMBOL_GPL(add_page_wait_queue);
*/
void unlock_page(struct page *page)
{
+ page = compound_head(page);
VM_BUG_ON_PAGE(!PageLocked(page), page);
clear_bit_unlock(PG_locked, &page->flags);
smp_mb__after_atomic();
@@ -873,18 +874,20 @@ EXPORT_SYMBOL_GPL(page_endio);
*/
void __lock_page(struct page *page)
{
- DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
+ struct page *page_head = compound_head(page);
+ DEFINE_WAIT_BIT(wait, &page_head->flags, PG_locked);
- __wait_on_bit_lock(page_waitqueue(page), &wait, bit_wait_io,
+ __wait_on_bit_lock(page_waitqueue(page_head), &wait, bit_wait_io,
TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(__lock_page);
int __lock_page_killable(struct page *page)
{
- DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
+ struct page *page_head = compound_head(page);
+ DEFINE_WAIT_BIT(wait, &page_head->flags, PG_locked);
- return __wait_on_bit_lock(page_waitqueue(page), &wait,
+ return __wait_on_bit_lock(page_waitqueue(page_head), &wait,
bit_wait_io, TASK_KILLABLE);
}
EXPORT_SYMBOL_GPL(__lock_page_killable);
diff -puN mm/ksm.c~page-flags-define-pg_locked-behavior-on-compound-pages mm/ksm.c
--- a/mm/ksm.c~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/mm/ksm.c
@@ -1884,7 +1884,7 @@ struct page *ksm_might_need_to_copy(stru
SetPageDirty(new_page);
__SetPageUptodate(new_page);
- __set_page_locked(new_page);
+ __SetPageLocked(new_page);
}
return new_page;
diff -puN mm/memory-failure.c~page-flags-define-pg_locked-behavior-on-compound-pages mm/memory-failure.c
--- a/mm/memory-failure.c~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/mm/memory-failure.c
@@ -1166,7 +1166,7 @@ int memory_failure(unsigned long pfn, in
/*
* We ignore non-LRU pages for good reasons.
* - PG_locked is only well defined for LRU pages and a few others
- * - to avoid races with __set_page_locked()
+ * - to avoid races with __SetPageLocked()
* - to avoid races with __SetPageSlab*() (and more non-atomic ops)
* The check (unnecessarily) ignores LRU pages being isolated and
* walked by the page reclaim code, however that's not a big loss.
diff -puN mm/migrate.c~page-flags-define-pg_locked-behavior-on-compound-pages mm/migrate.c
--- a/mm/migrate.c~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/mm/migrate.c
@@ -1765,7 +1765,7 @@ int migrate_misplaced_transhuge_page(str
flush_tlb_range(vma, mmun_start, mmun_end);
/* Prepare a page as a migration target */
- __set_page_locked(new_page);
+ __SetPageLocked(new_page);
SetPageSwapBacked(new_page);
/* anon mapping, we can simply copy page->mapping to the new page: */
diff -puN mm/shmem.c~page-flags-define-pg_locked-behavior-on-compound-pages mm/shmem.c
--- a/mm/shmem.c~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/mm/shmem.c
@@ -998,7 +998,7 @@ static int shmem_replace_page(struct pag
copy_highpage(newpage, oldpage);
flush_dcache_page(newpage);
- __set_page_locked(newpage);
+ __SetPageLocked(newpage);
SetPageUptodate(newpage);
SetPageSwapBacked(newpage);
set_page_private(newpage, swap_index);
@@ -1190,7 +1190,7 @@ repeat:
}
__SetPageSwapBacked(page);
- __set_page_locked(page);
+ __SetPageLocked(page);
if (sgp == SGP_WRITE)
__SetPageReferenced(page);
diff -puN mm/slub.c~page-flags-define-pg_locked-behavior-on-compound-pages mm/slub.c
--- a/mm/slub.c~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/mm/slub.c
@@ -338,11 +338,13 @@ static inline int oo_objects(struct kmem
*/
static __always_inline void slab_lock(struct page *page)
{
+ VM_BUG_ON_PAGE(PageTail(page), page);
bit_spin_lock(PG_locked, &page->flags);
}
static __always_inline void slab_unlock(struct page *page)
{
+ VM_BUG_ON_PAGE(PageTail(page), page);
__bit_spin_unlock(PG_locked, &page->flags);
}
diff -puN mm/swap_state.c~page-flags-define-pg_locked-behavior-on-compound-pages mm/swap_state.c
--- a/mm/swap_state.c~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/mm/swap_state.c
@@ -353,7 +353,7 @@ struct page *__read_swap_cache_async(swp
}
/* May fail (-ENOMEM) if radix-tree node allocation failed. */
- __set_page_locked(new_page);
+ __SetPageLocked(new_page);
SetPageSwapBacked(new_page);
err = __add_to_swap_cache(new_page, entry);
if (likely(!err)) {
@@ -367,7 +367,7 @@ struct page *__read_swap_cache_async(swp
}
radix_tree_preload_end();
ClearPageSwapBacked(new_page);
- __clear_page_locked(new_page);
+ __ClearPageLocked(new_page);
/*
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
* clear SWAP_HAS_CACHE flag.
diff -puN mm/vmscan.c~page-flags-define-pg_locked-behavior-on-compound-pages mm/vmscan.c
--- a/mm/vmscan.c~page-flags-define-pg_locked-behavior-on-compound-pages
+++ a/mm/vmscan.c
@@ -1184,7 +1184,7 @@ static unsigned long shrink_page_list(st
* we obviously don't have to worry about waking up a process
* waiting on the page lock, because there are no references.
*/
- __clear_page_locked(page);
+ __ClearPageLocked(page);
free_it:
nr_reclaimed++;
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
rcu-force-alignment-on-struct-callback_head-rcu_head.patch
mm-make-optimistic-check-for-swapin-readahead-fix.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-2.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-3.patch
mm-drop-page-slab_page.patch
slab-slub-use-page-rcu_head-instead-of-page-lru-plus-cast.patch
zsmalloc-use-page-private-instead-of-page-first_page.patch
mm-pack-compound_dtor-and-compound_order-into-one-word-in-struct-page.patch
mm-make-compound_head-robust.patch
mm-use-unsigned-int-for-page-order.patch
mm-use-unsigned-int-for-compound_dtor-compound_order-on-64bit.patch
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-move-code-around.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-at-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
mm-support-madvisemadv_free-fix-3.patch
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