diff options
| author | Pierre Peiffer <pierre.peiffer@bull.net> | 2007-05-09 02:35:02 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 12:30:55 -0700 |
| commit | c19384b5b296905d4988c7c684ff540a0f9d65be (patch) | |
| tree | 071cfe0855d409d63de80ec1b9b663738efb09de /include | |
| parent | ec92d08292d3e9b0823eba138a4564d2d39f25c7 (diff) | |
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 'include')
| -rw-r--r-- | include/linux/futex.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/futex.h b/include/linux/futex.h index 820125c628c..34e54f2b899 100644 --- a/include/linux/futex.h +++ b/include/linux/futex.h @@ -3,6 +3,8 @@ #include <linux/sched.h> +union ktime; + /* Second argument to futex syscall */ @@ -94,7 +96,7 @@ struct robust_list_head { #define ROBUST_LIST_LIMIT 2048 #ifdef __KERNEL__ -long do_futex(u32 __user *uaddr, int op, u32 val, unsigned long timeout, +long do_futex(u32 __user *uaddr, int op, u32 val, union ktime *timeout, u32 __user *uaddr2, u32 val2, u32 val3); extern int |