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| author |   Mikulas Patocka <mpatocka@redhat.com> | 2012-09-26 19:56:15 +0200 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2012-09-26 19:56:15 +0200 |
| commit | e6b5c0822bcf43b91a2cdcb535ea828e953b6590 (patch) | |
| tree | b6268cea3d80c7b43ac2d7fb8beb7c5e2063b57a /Documentation/percpu-rw-semaphore.txt | |
| parent | fs/block_dev.c:1644:5: sparse: symbol 'blkdev_mmap' was not declared (diff) | |
| download | linux-dev-e6b5c0822bcf43b91a2cdcb535ea828e953b6590.tar.xz linux-dev-e6b5c0822bcf43b91a2cdcb535ea828e953b6590.zip | |
percpu-rw-semaphore: fix documentation typos
One more patch for this thing, fixing some typos in the documentation.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation/percpu-rw-semaphore.txt')
| -rw-r--r-- | Documentation/percpu-rw-semaphore.txt | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/percpu-rw-semaphore.txt b/Documentation/percpu-rw-semaphore.txt index eddd77094725..7d3c82431909 100644 --- a/Documentation/percpu-rw-semaphore.txt +++ b/Documentation/percpu-rw-semaphore.txt @@ -9,10 +9,10 @@ cores take the lock for reading, the cache line containing the semaphore is bouncing between L1 caches of the cores, causing performance degradation. -Locking for reading it very fast, it uses RCU and it avoids any atomic +Locking for reading is very fast, it uses RCU and it avoids any atomic instruction in the lock and unlock path. On the other hand, locking for writing is very expensive, it calls synchronize_rcu() that can take -hundreds of microseconds. +hundreds of milliseconds. The lock is declared with "struct percpu_rw_semaphore" type. The lock is initialized percpu_init_rwsem, it returns 0 on success and |