diff options
| author | Nick Piggin <nickpiggin@yahoo.com.au> | 2005-07-07 17:56:56 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-07-07 18:23:45 -0700 |
| commit | a39722034ae37f80a1803bf781fe3fe1b03e20bc (patch) | |
| tree | fb7ef719d745e28678d73f884108f4cb2ef79171 | |
| parent | d6afe27bfff30fbec2cca6ad5626c22f4094d770 (diff) | |
[PATCH] page_uptodate locking scalability
Use a bit spin lock in the first buffer of the page to synchronise asynch
IO buffer completions, instead of the global page_uptodate_lock, which is
showing some scalabilty problems.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | fs/buffer.c | 25 | ||||
| -rw-r--r-- | include/linux/buffer_head.h | 3 |
2 files changed, 20 insertions, 8 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index 561e63a1496..6a25d7df89b 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -513,8 +513,8 @@ static void free_more_memory(void) */ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) { - static DEFINE_SPINLOCK(page_uptodate_lock); unsigned long flags; + struct buffer_head *first; struct buffer_head *tmp; struct page *page; int page_uptodate = 1; @@ -536,7 +536,9 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) * two buffer heads end IO at almost the same time and both * decide that the page is now completely done. */ - spin_lock_irqsave(&page_uptodate_lock, flags); + first = page_buffers(page); + local_irq_save(flags); + bit_spin_lock(BH_Uptodate_Lock, &first->b_state); clear_buffer_async_read(bh); unlock_buffer(bh); tmp = bh; @@ -549,7 +551,8 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) } tmp = tmp->b_this_page; } while (tmp != bh); - spin_unlock_irqrestore(&page_uptodate_lock, flags); + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); /* * If none of the buffers had errors and they are all @@ -561,7 +564,8 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) return; still_busy: - spin_unlock_irqrestore(&page_uptodate_lock, flags); + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); return; } @@ -572,8 +576,8 @@ still_busy: void end_buffer_async_write(struct buffer_head *bh, int uptodate) { char b[BDEVNAME_SIZE]; - static DEFINE_SPINLOCK(page_uptodate_lock); unsigned long flags; + struct buffer_head *first; struct buffer_head *tmp; struct page *page; @@ -594,7 +598,10 @@ void end_buffer_async_write(struct buffer_head *bh, int uptodate) SetPageError(page); } - spin_lock_irqsave(&page_uptodate_lock, flags); + first = page_buffers(page); + local_irq_save(flags); + bit_spin_lock(BH_Uptodate_Lock, &first->b_state); + clear_buffer_async_write(bh); unlock_buffer(bh); tmp = bh->b_this_page; @@ -605,12 +612,14 @@ void end_buffer_async_write(struct buffer_head *bh, int uptodate) } tmp = tmp->b_this_page; } - spin_unlock_irqrestore(&page_uptodate_lock, flags); + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); end_page_writeback(page); return; still_busy: - spin_unlock_irqrestore(&page_uptodate_lock, flags); + bit_spin_unlock(BH_Uptodate_Lock, &first->b_state); + local_irq_restore(flags); return; } diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 802c91e9b3d..90828493791 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -19,6 +19,9 @@ enum bh_state_bits { BH_Dirty, /* Is dirty */ BH_Lock, /* Is locked */ BH_Req, /* Has been submitted for I/O */ + BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise + * IO completion of other buffers in the page + */ BH_Mapped, /* Has a disk mapping */ BH_New, /* Disk mapping was newly created by get_block */ |