---
include/linux/mm.h | 2 +
include/linux/page-flags.h | 9 +++
include/linux/pagemap.h | 23 +++---
include/linux/writeback.h | 1 -
include/trace/events/mmflags.h | 1 +
init/main.c | 3 +-
mm/filemap.c | 180 +++++++++++++++++++++++++++++++++--------
mm/internal.h | 2 +
mm/swap.c | 2 +
9 files changed, 173 insertions(+), 50 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4424784ac374..fe6b4036664a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1758,6 +1758,8 @@ static inline spinlock_t *pmd_lock(struct mm_struct *mm,
pmd_t *pmd)
return ptl;
}
+extern void __init pagecache_init(void);
+
extern void free_area_init(unsigned long * zones_size);
extern void free_area_init_node(int nid, unsigned long * zones_size,
unsigned long zone_start_pfn, unsigned long *zholes_size);
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index a57c909a15e4..c56b39890a41 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -73,6 +73,7 @@
*/
enum pageflags {
PG_locked, /* Page is locked. Don't touch. */
+ PG_waiters, /* Page has waiters, check its waitqueue */
PG_error,
PG_referenced,
PG_uptodate,
@@ -169,6 +170,9 @@ static __always_inline int PageCompound(struct page *page)
* for compound page all operations related to the page flag applied to
* head page.
*
+ * PF_ONLY_HEAD:
+ * for compound page, callers only ever operate on the head page.
+ *
* PF_NO_TAIL:
* modifications of the page flag must be done on small or head pages,
* checks can be done on tail pages too.
@@ -178,6 +182,9 @@ static __always_inline int PageCompound(struct page *page)
*/
#define PF_ANY(page, enforce) page
#define PF_HEAD(page, enforce) compound_head(page)
+#define PF_ONLY_HEAD(page, enforce) ({ \
+ VM_BUG_ON_PGFLAGS(PageTail(page), page); \
+ page;})
#define PF_NO_TAIL(page, enforce) ({ \
VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
compound_head(page);})
@@ -255,6 +262,7 @@ static inline int TestClearPage##uname(struct page *page) {
return 0; }
TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
__PAGEFLAG(Locked, locked, PF_NO_TAIL)
+PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters,
PF_ONLY_HEAD)
PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error,
PF_NO_COMPOUND)
PAGEFLAG(Referenced, referenced, PF_HEAD)
TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
@@ -743,6 +751,7 @@ static inline int page_has_private(struct page *page)
#undef PF_ANY
#undef PF_HEAD
+#undef PF_ONLY_HEAD
#undef PF_NO_TAIL
#undef PF_NO_COMPOUND
#endif /* !__GENERATING_BOUNDS_H */
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 7dbe9148b2f8..d7f25f754d60 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -486,22 +486,14 @@ static inline int lock_page_or_retry(struct page *page,
struct mm_struct *mm,
* and for filesystems which need to wait on PG_private.
*/
extern void wait_on_page_bit(struct page *page, int bit_nr);
-
extern int wait_on_page_bit_killable(struct page *page, int bit_nr);
-extern int wait_on_page_bit_killable_timeout(struct page *page,
- int bit_nr, unsigned long timeout);
-
-static inline int wait_on_page_locked_killable(struct page *page)
-{
- if (!PageLocked(page))
- return 0;
- return wait_on_page_bit_killable(compound_head(page), PG_locked);
-}
+extern void wake_up_page_bit(struct page *page, int bit_nr);
-extern wait_queue_head_t *page_waitqueue(struct page *page);
static inline void wake_up_page(struct page *page, int bit)
{
- __wake_up_bit(page_waitqueue(page), &page->flags, bit);
+ if (!PageWaiters(page))
+ return;
+ wake_up_page_bit(page, bit);
}
/*
@@ -517,6 +509,13 @@ static inline void wait_on_page_locked(struct page *page)
wait_on_page_bit(compound_head(page), PG_locked);
}
+static inline int wait_on_page_locked_killable(struct page *page)
+{
+ if (!PageLocked(page))
+ return 0;
+ return wait_on_page_bit_killable(compound_head(page), PG_locked);
+}
+
/*
* Wait for a page to complete writeback
*/
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index c78f9f0920b5..5527d910ba3d 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -375,7 +375,6 @@ void global_dirty_limits(unsigned long *pbackground,
unsigned long *pdirty);
unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh);
void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time);
-void page_writeback_init(void);
void balance_dirty_pages_ratelimited(struct address_space *mapping);
bool wb_over_bg_thresh(struct bdi_writeback *wb);
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 30c2adbdebe8..9e687ca9a307 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -81,6 +81,7 @@
#define __def_pageflag_names \
{1UL << PG_locked, "locked" }, \
+ {1UL << PG_waiters, "waiters" }, \
{1UL << PG_error, "error" }, \
{1UL << PG_referenced, "referenced" }, \
{1UL << PG_uptodate, "uptodate" }, \
diff --git a/init/main.c b/init/main.c
index c81c9fa21bc7..b0c9d6facef9 100644
--- a/init/main.c
+++ b/init/main.c
@@ -647,9 +647,8 @@ asmlinkage __visible void __init start_kernel(void)
security_init();
dbg_late_init();
vfs_caches_init();
+ pagecache_init();
signals_init();
- /* rootfs populating might need page-writeback */
- page_writeback_init();
proc_root_init();
nsfs_init();
cpuset_init();
diff --git a/mm/filemap.c b/mm/filemap.c
index 32be3c8f3a11..f138dc324fa4 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -739,45 +739,158 @@ EXPORT_SYMBOL(__page_cache_alloc);
* at a cost of "thundering herd" phenomena during rare hash
* collisions.
*/
-wait_queue_head_t *page_waitqueue(struct page *page)
+#define PAGE_WAIT_TABLE_BITS 8
+#define PAGE_WAIT_TABLE_SIZE (1 << PAGE_WAIT_TABLE_BITS)
+static wait_queue_head_t page_wait_table[PAGE_WAIT_TABLE_SIZE]
__cacheline_aligned;
+
+static wait_queue_head_t *page_waitqueue(struct page *page)
{
- return bit_waitqueue(page, 0);
+ return &page_wait_table[hash_ptr(page, PAGE_WAIT_TABLE_BITS)];
}
-EXPORT_SYMBOL(page_waitqueue);
-void wait_on_page_bit(struct page *page, int bit_nr)
+void __init pagecache_init(void)
{
- DEFINE_WAIT_BIT(wait, &page->flags, bit_nr);
+ int i;
- if (test_bit(bit_nr, &page->flags))
- __wait_on_bit(page_waitqueue(page), &wait, bit_wait_io,
- TASK_UNINTERRUPTIBLE);
+ for (i = 0; i < PAGE_WAIT_TABLE_SIZE; i++)
+ init_waitqueue_head(&page_wait_table[i]);
+
+ page_writeback_init();
}
-EXPORT_SYMBOL(wait_on_page_bit);
-int wait_on_page_bit_killable(struct page *page, int bit_nr)
+struct wait_page_key {
+ struct page *page;
+ int bit_nr;
+ int page_match;
+};
+
+struct wait_page_queue {
+ struct page *page;
+ int bit_nr;
+ wait_queue_t wait;
+};
+
+static int wake_page_function(wait_queue_t *wait, unsigned mode, int sync,
void *arg)
{
- DEFINE_WAIT_BIT(wait, &page->flags, bit_nr);
+ struct wait_page_key *key = arg;
+ struct wait_page_queue *wait_page
+ = container_of(wait, struct wait_page_queue, wait);
+
+ if (wait_page->page != key->page)
+ return 0;
+ key->page_match = 1;
- if (!test_bit(bit_nr, &page->flags))
+ if (wait_page->bit_nr != key->bit_nr)
+ return 0;
+ if (test_bit(key->bit_nr, &key->page->flags))
return 0;
- return __wait_on_bit(page_waitqueue(page), &wait,
- bit_wait_io, TASK_KILLABLE);
+ return autoremove_wake_function(wait, mode, sync, key);
}
-int wait_on_page_bit_killable_timeout(struct page *page,
- int bit_nr, unsigned long timeout)
+void wake_up_page_bit(struct page *page, int bit_nr)
{
- DEFINE_WAIT_BIT(wait, &page->flags, bit_nr);
+ wait_queue_head_t *q = page_waitqueue(page);
+ struct wait_page_key key;
+ unsigned long flags;
- wait.key.timeout = jiffies + timeout;
- if (!test_bit(bit_nr, &page->flags))
- return 0;
- return __wait_on_bit(page_waitqueue(page), &wait,
- bit_wait_io_timeout, TASK_KILLABLE);
+ key.page = page;
+ key.bit_nr = bit_nr;
+ key.page_match = 0;
+
+ spin_lock_irqsave(&q->lock, flags);
+ __wake_up_locked_key(q, TASK_NORMAL, &key);
+ /*
+ * It is possible for other pages to have collided on the waitqueue
+ * hash, so in that case check for a page match. That prevents a long-
+ * term waiter
+ *
+ * It is still possible to miss a case here, when we woke page waiters
+ * and removed them from the waitqueue, but there are still other
+ * page waiters.
+ */
+ if (!waitqueue_active(q) || !key.page_match) {
+ ClearPageWaiters(page);
+ /*
+ * It's possible to miss clearing Waiters here, when we woke
+ * our page waiters, but the hashed waitqueue has waiters for
+ * other pages on it.
+ *
+ * That's okay, it's a rare case. The next waker will clear it.
+ */
+ }
+ spin_unlock_irqrestore(&q->lock, flags);
+}
+EXPORT_SYMBOL(wake_up_page_bit);
+
+static inline int wait_on_page_bit_common(wait_queue_head_t *q,
+ struct page *page, int bit_nr, int state, bool lock)
+{
+ struct wait_page_queue wait_page;
+ wait_queue_t *wait = &wait_page.wait;
+ int ret = 0;
+
+ init_wait(wait);
+ wait->func = wake_page_function;
+ wait_page.page = page;
+ wait_page.bit_nr = bit_nr;
+
+ for (;;) {
+ spin_lock_irq(&q->lock);
+
+ if (likely(list_empty(&wait->task_list))) {
+ if (lock)
+ __add_wait_queue_tail_exclusive(q, wait);
+ else
+ __add_wait_queue(q, wait);
+ SetPageWaiters(page);
+ }
+
+ set_current_state(state);
+
+ spin_unlock_irq(&q->lock);
+
+ if (likely(test_bit(bit_nr, &page->flags))) {
+ io_schedule();
+ if (unlikely(signal_pending_state(state, current))) {
+ ret = -EINTR;
+ break;
+ }
+ }
+
+ if (lock) {
+ if (!test_and_set_bit_lock(bit_nr, &page->flags))
+ break;
+ } else {
+ if (!test_bit(bit_nr, &page->flags))
+ break;
+ }
+ }
+
+ finish_wait(q, wait);
+
+ /*
+ * A signal could leave PageWaiters set. Clearing it here if
+ * !waitqueue_active would be possible, but still fail to catch it in
+ * the case of wait hash collision. We already can fail to clear wait
+ * hash collision cases, so don't bother with signals either.
+ */
+
+ return ret;
+}
+
+void wait_on_page_bit(struct page *page, int bit_nr)
+{
+ wait_queue_head_t *q = page_waitqueue(page);
+ wait_on_page_bit_common(q, page, bit_nr, TASK_UNINTERRUPTIBLE, false);
+}
+EXPORT_SYMBOL(wait_on_page_bit);
+
+int wait_on_page_bit_killable(struct page *page, int bit_nr)
+{
+ wait_queue_head_t *q = page_waitqueue(page);
+ return wait_on_page_bit_common(q, page, bit_nr, TASK_KILLABLE, false);
}
-EXPORT_SYMBOL_GPL(wait_on_page_bit_killable_timeout);
/**
* add_page_wait_queue - Add an arbitrary waiter to a page's wait queue
@@ -793,6 +906,7 @@ void add_page_wait_queue(struct page *page, wait_queue_t
*waiter)
spin_lock_irqsave(&q->lock, flags);
__add_wait_queue(q, waiter);
+ SetPageWaiters(page);
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL_GPL(add_page_wait_queue);
@@ -874,23 +988,19 @@ EXPORT_SYMBOL_GPL(page_endio);
* __lock_page - get a lock on the page, assuming we need to sleep to get it
* @page: the page to lock
*/
-void __lock_page(struct page *page)
+void __lock_page(struct page *__page)
{
- struct page *page_head = compound_head(page);
- DEFINE_WAIT_BIT(wait, &page_head->flags, PG_locked);
-
- __wait_on_bit_lock(page_waitqueue(page_head), &wait, bit_wait_io,
- TASK_UNINTERRUPTIBLE);
+ struct page *page = compound_head(__page);
+ wait_queue_head_t *q = page_waitqueue(page);
+ wait_on_page_bit_common(q, page, PG_locked, TASK_UNINTERRUPTIBLE, true);
}
EXPORT_SYMBOL(__lock_page);
-int __lock_page_killable(struct page *page)
+int __lock_page_killable(struct page *__page)
{
- struct page *page_head = compound_head(page);
- DEFINE_WAIT_BIT(wait, &page_head->flags, PG_locked);
-
- return __wait_on_bit_lock(page_waitqueue(page_head), &wait,
- bit_wait_io, TASK_KILLABLE);
+ struct page *page = compound_head(__page);
+ wait_queue_head_t *q = page_waitqueue(page);
+ return wait_on_page_bit_common(q, page, PG_locked, TASK_KILLABLE, true);
}
EXPORT_SYMBOL_GPL(__lock_page_killable);
diff --git a/mm/internal.h b/mm/internal.h
index 44d68895a9b9..7aa2ea0a8623 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -36,6 +36,8 @@
/* Do not use these with a slab allocator */
#define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
+void page_writeback_init(void);
+
int do_swap_page(struct vm_fault *vmf);
void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
diff --git a/mm/swap.c b/mm/swap.c
index 4dcf852e1e6d..844baedd2429 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -69,6 +69,7 @@ static void __page_cache_release(struct page *page)
del_page_from_lru_list(page, lruvec, page_off_lru(page));
spin_unlock_irqrestore(zone_lru_lock(zone), flags);
}
+ __ClearPageWaiters(page);
mem_cgroup_uncharge(page);
}
@@ -784,6 +785,7 @@ void release_pages(struct page **pages, int nr, bool cold)
/* Clear Active bit in case of parallel mark_page_accessed */
__ClearPageActive(page);
+ __ClearPageWaiters(page);
list_add(&page->lru, &pages_to_free);
}
--
2.11.0
