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author | Pierre Peiffer <pierre.peiffer@bull.net> | 2007-05-09 09:35:02 (GMT) |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 19:30:55 (GMT) |
commit | c19384b5b296905d4988c7c684ff540a0f9d65be (patch) | |
tree | 071cfe0855d409d63de80ec1b9b663738efb09de /kernel/rtmutex_common.h | |
parent | ec92d08292d3e9b0823eba138a4564d2d39f25c7 (diff) | |
download | linux-c19384b5b296905d4988c7c684ff540a0f9d65be.tar.xz |
Make futex_wait() use an hrtimer for timeout
This patch modifies futex_wait() to use an hrtimer + schedule() in place of
schedule_timeout().
schedule_timeout() is tick based, therefore the timeout granularity is the
tick (1 ms, 4 ms or 10 ms depending on HZ). By using a high resolution timer
for timeout wakeup, we can attain a much finer timeout granularity (in the
microsecond range). This parallels what is already done for futex_lock_pi().
The timeout passed to the syscall is no longer converted to jiffies and is
therefore passed to do_futex() and futex_wait() as an absolute ktime_t
therefore keeping nanosecond resolution.
Also this removes the need to pass the nanoseconds timeout part to
futex_lock_pi() in val2.
In futex_wait(), if there is no timeout then a regular schedule() is
performed. Otherwise, an hrtimer is fired before schedule() is called.
[akpm@linux-foundation.org: fix `make headers_check']
Signed-off-by: Sebastien Dugue <sebastien.dugue@bull.net>
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/rtmutex_common.h')
0 files changed, 0 insertions, 0 deletions