lkml.org 
[lkml]   [2012]   [Feb]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH RFC tip/core/rcu 04/41] rcu: Add diagnostic for misaligned rcu_head structures
    On Wed, Feb 01, 2012 at 11:41:22AM -0800, Paul E. McKenney wrote:
    > The push for energy efficiency will require that RCU tag rcu_head
    > structures to indicate whether or not their invocation is time critical.
    > This tagging is best carried out in the bottom bits of the ->next
    > pointers in the rcu_head structures. This tagging requires that the
    > rcu_head structures be properly aligned, so this commit adds the required
    > diagnostics.

    > --- a/kernel/rcutree.c
    > +++ b/kernel/rcutree.c
    > @@ -1707,6 +1707,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
    > unsigned long flags;
    > struct rcu_data *rdp;
    >
    > + WARN_ON_ONCE((unsigned long)head & 0x3); /* Misaligned rcu_head! */

    I wonder if this should go out in one of the wrapper macros, so that the
    _ONCE means once per call site?

    - Josh Triplett


    \
     
     \ /
      Last update: 2012-02-02 02:03    [W:0.020 / U:60.596 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site