Re: [PATCH tip/core/rcu 1/4] mce: Stop using array-index-based RCU primitives

From: Borislav Petkov
Date: Wed May 13 2015 - 06:32:07 EST

On Tue, May 12, 2015 at 02:18:41PM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
> Because mce is arch-specific x86 code, there is little or no
> performance benefit of using rcu_dereference_index_check() over using
> smp_load_acquire(). It also turns out that mce is the only place that
> array-index-based RCU is used, and it would be convenient to drop
> this portion of the RCU API.
> This patch therefore changes rcu_dereference_index_check() uses to
> smp_load_acquire(), but keeping the lockdep diagnostics, and also
> changes rcu_access_index() uses to READ_ONCE().
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> Cc: linux-edac@xxxxxxxxxxxxxxx
> Cc: Tony Luck <tony.luck@xxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>

Looks good to me.

If it is easier for you carrying it in your tree:

Acked-by: Borislav Petkov <bp@xxxxxxx>

Otherwise, let me know.



ECO tip #101: Trim your mails when you reply.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at