Re: [PATCH 1/3] static_keys: Add a static_key_slow_set_true()/false() interface

2013-06-28 Thread Steven Rostedt
On Fri, 2013-06-28 at 22:30 +, jba...@akamai.com wrote: > As pointed out by Andi Kleen, some static key users can be racy because they > check the value of the key->enabled, and then subsequently update the branch > direction. A number of call sites have 'higher' level locking that avoids this

[PATCH 1/3] static_keys: Add a static_key_slow_set_true()/false() interface

2013-06-28 Thread jbaron
As pointed out by Andi Kleen, some static key users can be racy because they check the value of the key->enabled, and then subsequently update the branch direction. A number of call sites have 'higher' level locking that avoids this race, but the usage in the scheduler features does not. See: http: