GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-07-06 22:42:10 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Make futex_wait() use an hrtimer for timeout

Browse source 
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>
This commit is contained in:
Pierre Peiffer 2007-05-09 02:35:02 -07:00 • committed by Linus Torvalds
parent ec92d08292
commit c19384b5b2
3 changed files with 56 additions and 54 deletions
Download patch file Download diff file Expand all files Collapse all files

4
include/linux/futex.h
View file

@ -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