diff options
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | include/linux/page-flags.h | 9 | ||||
| -rw-r--r-- | include/linux/pagemap.h | 23 | ||||
| -rw-r--r-- | include/linux/writeback.h | 1 | ||||
| -rw-r--r-- | include/trace/events/mmflags.h | 1 | ||||
| -rw-r--r-- | init/main.c | 3 | ||||
| -rw-r--r-- | mm/filemap.c | 181 | ||||
| -rw-r--r-- | mm/internal.h | 2 | ||||
| -rw-r--r-- | mm/swap.c | 2 |
9 files changed, 174 insertions, 50 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 4424784..fe6b403 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 a57c909..c56b398 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 f29f80f..324c8dba 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 c78f9f0..5527d91 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 30c2adb..9e687ca 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 c81c9fa..b0c9d6f 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 32be3c8..82f26cd 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -739,45 +739,159 @@ 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 (by open-coding finish_wait), + * 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 +907,7 @@ 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 +989,19 @@ 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 44d6889..7aa2ea0 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, @@ -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); } |
