Messages in this thread | | | Date | Tue, 30 Sep 2014 15:49:28 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 10/11] sched: Debug nested sleeps |
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On Tue, Sep 30, 2014 at 12:13:44AM +0200, Oleg Nesterov wrote: > On 09/24, Peter Zijlstra wrote: > > > > +#ifdef CONFIG_DEBUG_ATOMIC_SLEEP > > + > > +#define __set_task_state(tsk, state_value) \ > > + do { \ > > + (tsk)->task_state_change = _THIS_IP_; \ > > + (tsk)->state = (state_value); \ > > + } while (0) > > ... > > > @@ -7143,6 +7143,19 @@ void __might_sleep(const char *file, int > > { > > static unsigned long prev_jiffy; /* ratelimiting */ > > > > + /* > > + * Blocking primitives will set (and therefore destroy) current->state, > > + * since we will exit with TASK_RUNNING make sure we enter with it, > > + * otherwise we will destroy state. > > + */ > > + if (WARN(current->state != TASK_RUNNING, > > + "do not call blocking ops when !TASK_RUNNING; " > > + "state=%lx set at [<%p>] %pS\n", > > + current->state, > > + (void *)current->task_state_change, > > + (void *)current->task_state_change)) > > + __set_current_state(TASK_RUNNING); > > Question: now that we have ->task_state_change, perhaps it makes sense > to redefine fixup_sleep() > > #ifdef CONFIG_DEBUG_ATOMIC_SLEEP > #define fixup_sleep() (current->task_state_change = 0) > #else > #define fixup_sleep() do { } while (0) > #endif > > and make the WARN() above depend on task_state_change != 0 ? > > This is minor, but this way CONFIG_DEBUG_ATOMIC_SLEEP will not imply > a subtle behavioural change.
You mean the __set_current_state() that's extra? I would actually argue to keep that since it makes the 'problem' much worse.
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