Messages in this thread Patch in this message | | | Subject | Re: [PATCH 6/7 linux-next] wan: cosa: replace current->state by set_current_state() | From | Eric Dumazet <> | Date | Fri, 20 Feb 2015 11:31:53 -0800 |
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On Fri, 2015-02-20 at 19:58 +0100, Peter Zijlstra wrote: > On Fri, Feb 20, 2015 at 09:34:28PM +0300, Sergei Shtylyov wrote: > > Hello. > > > > On 02/20/2015 09:12 PM, Fabian Frederick wrote: > > > > >Use helper functions to access current->state. > > >Direct assignments are prone to races and therefore buggy. > > > > >current->state = TASK_RUNNING is replaced by __set_current_state() > > > > You sometimes use __set_current_state() and sometimes set_current_state(). > > It depends on which state; setting yourself TASK_RUNNING is free of > wakeup races -- you're already running after all, so it can safely use > __set_current_state().
Maybe this might be self documented in set_current_state(), as we have about 120 calls to __set_current_state(TASK_RUNNING)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 41c60e5302d7..26133da6445e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -275,7 +275,11 @@ extern char ___assert_task_state[1 - 2*!!( #define set_current_state(state_value) \ do { \ current->task_state_change = _THIS_IP_; \ - set_mb(current->state, (state_value)); \ + if (__builtin_constant_p(state_value) && \ + (state_value) == TASK_RUNNING) \ + current->state = (state_value); \ + else \ + set_mb(current->state, (state_value)); \ } while (0) #else
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