On Thu, Jun 23, 2016 at 07:26:52PM +0200, Thomas Gleixner wrote:
> On Thu, 23 Jun 2016, Darren Hart wrote:
> > On Thu, Jun 23, 2016 at 03:40:36PM +0200, Thomas Gleixner wrote:
> > In my opinion, we should treat the timeout value as relative for FUTEX_WAIT
> > regardless of the CLOCK used.
>
> Which requires even more changes as you have to select which clock you are
> using for adding the base time.
Right, something like the following?
diff --git a/kernel/futex.c b/kernel/futex.c
index 33664f7..c39d807 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3230,8 +3230,12 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op,
u32, val,
return -EINVAL;
t = timespec_to_ktime(ts);
- if (cmd == FUTEX_WAIT)
- t = ktime_add_safe(ktime_get(), t);
+ if (cmd == FUTEX_WAIT) {
+ if (cmd & FUTEX_CLOCK_REALTIME)
+ t = ktime_add_safe(ktime_get_real(), t);
+ else
+ t = ktime_add_safe(ktime_get(), t);
+ }
tp = &t;
}
/*
And as a follow-on, what is the reason for FUTEX_LOCK_PI only using
CLOCK_REALTIME? It seems reasonable to me that a user may want to wait a
specific amount of time, regardless of wall time.
--
Darren Hart
Intel Open Source Technology Center
