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| author | Jens Axboe <axboe@suse.de> | 2006-04-10 09:03:32 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@suse.de> | 2006-04-10 09:03:32 +0200 |
| commit | c0bd1f650bd06a43435808d44f1e9520ea806206 (patch) | |
| tree | e2f4480a1bc08d9044f66c44174273abea7e0c58 /fs/splice.c | |
| parent | 9aefe431f5a000884db7ae74ac208de814fe5913 (diff) | |
| download | lwn-c0bd1f650bd06a43435808d44f1e9520ea806206.tar.gz lwn-c0bd1f650bd06a43435808d44f1e9520ea806206.zip | |
[PATCH] splice: only call wake_up_interruptible() when we really have to
__wake_up_common() is pretty heavy in the kernel profiles, this brings
it down to a more acceptable level.
Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'fs/splice.c')
| -rw-r--r-- | fs/splice.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/fs/splice.c b/fs/splice.c index 26f5f7ecee5c..9f796b1034d1 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -187,7 +187,9 @@ static ssize_t move_to_pipe(struct inode *inode, struct page **pages, } if (do_wakeup) { - wake_up_interruptible_sync(PIPE_WAIT(*inode)); + smp_mb(); + if (waitqueue_active(PIPE_WAIT(*inode))) + wake_up_interruptible_sync(PIPE_WAIT(*inode)); kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); do_wakeup = 0; @@ -201,7 +203,9 @@ static ssize_t move_to_pipe(struct inode *inode, struct page **pages, mutex_unlock(PIPE_MUTEX(*inode)); if (do_wakeup) { - wake_up_interruptible(PIPE_WAIT(*inode)); + smp_mb(); + if (waitqueue_active(PIPE_WAIT(*inode))) + wake_up_interruptible(PIPE_WAIT(*inode)); kill_fasync(PIPE_FASYNC_READERS(*inode), SIGIO, POLL_IN); } @@ -600,7 +604,9 @@ static ssize_t move_from_pipe(struct inode *inode, struct file *out, } if (do_wakeup) { - wake_up_interruptible_sync(PIPE_WAIT(*inode)); + smp_mb(); + if (waitqueue_active(PIPE_WAIT(*inode))) + wake_up_interruptible_sync(PIPE_WAIT(*inode)); kill_fasync(PIPE_FASYNC_WRITERS(*inode),SIGIO,POLL_OUT); do_wakeup = 0; } @@ -611,7 +617,9 @@ static ssize_t move_from_pipe(struct inode *inode, struct file *out, mutex_unlock(PIPE_MUTEX(*inode)); if (do_wakeup) { - wake_up_interruptible(PIPE_WAIT(*inode)); + smp_mb(); + if (waitqueue_active(PIPE_WAIT(*inode))) + wake_up_interruptible(PIPE_WAIT(*inode)); kill_fasync(PIPE_FASYNC_WRITERS(*inode), SIGIO, POLL_OUT); } |