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 <[email protected]>
Thu, 3 Apr 2008 07:06:13 +0000 (09:06 +0200)
committer Ingo Molnar <[email protected]>
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;
}