HR timers:

From: Michal Simek
Date: Fri Jul 11 2008 - 08:28:40 EST


Hi Ingo,

I debug Microblaze kernel and I found one big problem which comes with your patch.
Here is more detail about patch (latest patch linux/kernel/git/torvalds/linux-2.6.git/include/linux/seqlock.h)

author Ingo Molnar <mingo@xxxxxxx>
Thu, 3 Apr 2008 07:06:13 +0000 (09:06 +0200)
committer Ingo Molnar <mingo@xxxxxxx>
Thu, 24 Apr 2008 22:25:08 +0000 (00:25 +0200)
commit 88a411c07b6fedcfc97b8dc51ae18540bd2beda0

You add there checking mechanism to (read_seqbegin and read_seqcount_begin) where you are checking
odd value in ret variable. I don't know yet why I got there odd value (0x3553). What does it mean the odd bit here?
I read any comment about tick_oneshot code.

Could you explain me what is broken?

Thanks for your help,
Michal Simek

static __always_inline unsigned read_seqbegin(const seqlock_t *sl)
{
- unsigned ret = sl->sequence;
+ unsigned ret;
+
+repeat:
+ ret = sl->sequence;
smp_rmb();
+ if (unlikely(ret & 1)) {
+ cpu_relax();
+ goto repeat;
+ }
+
return ret;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/