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rcu: Make rcu_read_lock_sched_held() take boot time into account

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Before the scheduler starts, all tasks are non-preemptible by
definition. So, during that time, rcu_read_lock_sched_held()
needs to always return "true".  This patch makes that be so.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1267135607-7056-2-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul E. McKenney 2010-02-25 14:06:47 -08:00 • committed by Ingo Molnar
commit d9f1bb6ad7
5 changed files with 21 additions and 25 deletions
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4
include/linux/rcupdate.h
View file

@ -62,6 +62,8 @@ extern int sched_expedited_torture_stats(char *page);
/* Internal to kernel */
extern void rcu_init(void);
extern int rcu_scheduler_active;
extern void rcu_scheduler_starting(void);
#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
#include <linux/rcutree.h>
@ -140,7 +142,7 @@ static inline int rcu_read_lock_sched_held(void)
if (debug_locks)
lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
return lockdep_opinion || preempt_count() != 0;
return lockdep_opinion || preempt_count() != 0 || !rcu_scheduler_active;
}
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */