diff options
Diffstat (limited to 'innobase/include/buf0buf.h')
| -rw-r--r-- | innobase/include/buf0buf.h | 40 |
1 files changed, 28 insertions, 12 deletions
diff --git a/innobase/include/buf0buf.h b/innobase/include/buf0buf.h index fc1d9a64c7f..11e5bb39e63 100644 --- a/innobase/include/buf0buf.h +++ b/innobase/include/buf0buf.h @@ -461,8 +461,8 @@ Gets the mutex number protecting the page record lock hash chain in the lock table. */ UNIV_INLINE mutex_t* -buf_frame_get_lock_mutex( -/*=====================*/ +buf_frame_get_mutex( +/*================*/ /* out: mutex */ byte* ptr); /* in: pointer to within a buffer frame */ /*********************************************************************** @@ -713,7 +713,10 @@ struct buf_block_struct{ ulint magic_n; /* magic number to check */ ulint state; /* state of the control block: - BUF_BLOCK_NOT_USED, ... */ + BUF_BLOCK_NOT_USED, ...; changing + this is only allowed when a thread + has BOTH the buffer pool mutex AND + block->mutex locked */ byte* frame; /* pointer to buffer frame which is of size UNIV_PAGE_SIZE, and aligned to an address divisible by @@ -731,8 +734,12 @@ struct buf_block_struct{ ulint offset; /* page number within the space */ ulint lock_hash_val; /* hashed value of the page address in the record lock hash table */ - mutex_t* lock_mutex; /* mutex protecting the chain in the - record lock hash table */ + mutex_t mutex; /* mutex protecting this block: + state (also protected by the buffer + pool mutex), io_fix, buf_fix_count, + and accessed; we introduce this new + mutex in InnoDB-5.1 to relieve + contention on the buffer pool mutex */ rw_lock_t lock; /* read-write lock of the buffer frame */ buf_block_t* hash; /* node used in chaining to the page @@ -788,20 +795,27 @@ struct buf_block_struct{ in heuristic algorithms, because of the possibility of a wrap-around! */ ulint freed_page_clock;/* the value of freed_page_clock - buffer pool when this block was - last time put to the head of the - LRU list */ + of the buffer pool when this block was + the last time put to the head of the + LRU list; a thread is allowed to + read this for heuristic purposes + without holding any mutex or latch */ ibool old; /* TRUE if the block is in the old blocks in the LRU list */ ibool accessed; /* TRUE if the page has been accessed while in the buffer pool: read-ahead may read in pages which have not been - accessed yet */ + accessed yet; this is protected by + block->mutex; a thread is allowed to + read this for heuristic purposes + without holding any mutex or latch */ ulint buf_fix_count; /* count of how manyfold this block - is currently bufferfixed */ + is currently bufferfixed; this is + protected by block->mutex */ ulint io_fix; /* if a read is pending to the frame, io_fix is BUF_IO_READ, in the case - of a write BUF_IO_WRITE, otherwise 0 */ + of a write BUF_IO_WRITE, otherwise 0; + this is protected by block->mutex */ /* 4. Optimistic search field */ dulint modify_clock; /* this clock is incremented every @@ -962,7 +976,9 @@ struct buf_pool_struct{ number of buffer blocks removed from the end of the LRU list; NOTE that this counter may wrap around at 4 - billion! */ + billion! A thread is allowed to + read this for heuristic purposes + without holding any mutex or latch */ ulint LRU_flush_ended;/* when an LRU flush ends for a page, this is incremented by one; this is set to zero when a buffer block is |