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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-01-16 03:51:24 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-16 04:56:32 +0300
commit48c935ad88f5be20eb5445a77c171351b1eb5111 (patch)
tree727050f571933315f65a956b6cb72a01f1028f9d
parent95ad97554ac81b31139d4fe5ed8757a07087cd90 (diff)
downloadlinux-48c935ad88f5be20eb5445a77c171351b1eb5111.tar.xz
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. [akpm@linux-foundation.org: fix fs/cifs/file.c] Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Jérôme Glisse <jglisse@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/cifs/file.c8
-rw-r--r--include/linux/page-flags.h2
-rw-r--r--include/linux/pagemap.h25
-rw-r--r--mm/filemap.c15
-rw-r--r--mm/ksm.c2
-rw-r--r--mm/memory-failure.c2
-rw-r--r--mm/migrate.c2
-rw-r--r--mm/shmem.c4
-rw-r--r--mm/slub.c2
-rw-r--r--mm/swap_state.c4
-rw-r--r--mm/vmscan.c2
11 files changed, 32 insertions, 36 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0068e82217c3..0a2752b79e72 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3391,13 +3391,13 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
* should have access to this page, we're safe to simply set
* PG_locked without checking it first.
*/
- __set_page_locked(page);
+ __SetPageLocked(page);
rc = add_to_page_cache_locked(page, mapping,
page->index, gfp);
/* give up if we can't stick it in the cache */
if (rc) {
- __clear_page_locked(page);
+ __ClearPageLocked(page);
return rc;
}
@@ -3418,9 +3418,9 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
if (*bytes + PAGE_CACHE_SIZE > rsize)
break;
- __set_page_locked(page);
+ __SetPageLocked(page);
if (add_to_page_cache_locked(page, mapping, page->index, gfp)) {
- __clear_page_locked(page);
+ __ClearPageLocked(page);
break;
}
list_move_tail(&page->lru, tmplist);
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 12ab023b67f2..32c87eb470cb 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -256,7 +256,7 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; }
#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 --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 26eabf5ec718..df214a4b886d 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -433,18 +433,9 @@ extern int __lock_page_or_retry(struct page *page, struct mm_struct *mm,
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)));
}
@@ -497,9 +488,9 @@ extern int wait_on_page_bit_killable_timeout(struct page *page,
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);
@@ -518,7 +509,7 @@ static inline void wake_up_page(struct page *page, int bit)
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);
}
/*
@@ -664,17 +655,17 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
/*
* 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 --git a/mm/filemap.c b/mm/filemap.c
index ff42d31c891a..ae652ded700c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -682,11 +682,11 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
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 --git a/mm/ksm.c b/mm/ksm.c
index 2d162c5625f6..643abe7a75de 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1899,7 +1899,7 @@ struct page *ksm_might_need_to_copy(struct page *page,
SetPageDirty(new_page);
__SetPageUptodate(new_page);
- __set_page_locked(new_page);
+ __SetPageLocked(new_page);
}
return new_page;
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 8424b64711ac..5b965e27aaae 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1166,7 +1166,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
/*
* 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 --git a/mm/migrate.c b/mm/migrate.c
index 7890d0bb5e23..f7f345ddc9ae 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1767,7 +1767,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
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 --git a/mm/shmem.c b/mm/shmem.c
index 970ff5b80853..d271932f9ef9 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1085,7 +1085,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
copy_highpage(newpage, oldpage);
flush_dcache_page(newpage);
- __set_page_locked(newpage);
+ __SetPageLocked(newpage);
SetPageUptodate(newpage);
SetPageSwapBacked(newpage);
set_page_private(newpage, swap_index);
@@ -1277,7 +1277,7 @@ repeat:
}
__SetPageSwapBacked(page);
- __set_page_locked(page);
+ __SetPageLocked(page);
if (sgp == SGP_WRITE)
__SetPageReferenced(page);
diff --git a/mm/slub.c b/mm/slub.c
index 2d0e610d195a..b21fd24b08b1 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -338,11 +338,13 @@ static inline int oo_objects(struct kmem_cache_order_objects x)
*/
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 --git a/mm/swap_state.c b/mm/swap_state.c
index d504adb7fa5f..d783872d746c 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -353,7 +353,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
}
/* 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_entry_t entry, gfp_t gfp_mask,
}
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 --git a/mm/vmscan.c b/mm/vmscan.c
index 108bd119f2f6..983e407afc09 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1184,7 +1184,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* 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++;