Messages in this thread | | | Date | Wed, 15 Jul 2015 15:52:34 +0300 | From | Konstantin Khlebnikov <> | Subject | Re: [PATCH v2 3/3] sched/preempt: fix cond_resched_lock() and cond_resched_softirq() |
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On 15.07.2015 15:16, Eric Dumazet wrote: > On Wed, 2015-07-15 at 12:52 +0300, Konstantin Khlebnikov wrote: >> These functions check should_resched() before unlocking spinlock/bh-enable: >> preempt_count always non-zero => should_resched() always returns false. >> cond_resched_lock() worked iff spin_needbreak is set. > > Interesting, this definitely used to work (linux-3.11) > > Any idea of which commit broke things ? >
Searching... done
This one: bdb43806589096ac4272fe1307e789846ac08d7c in v3.13
before
-static inline int should_resched(void) -{ - return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); -}
after
+static __always_inline bool should_resched(void) +{ + return unlikely(!*preempt_count_ptr()); +}
So,
Fixes: bdb438065890 ("sched: Extract the basic add/sub preempt_count modifiers")
-- Konstantin
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