On Tue, Oct 08, 2013 at 12:25:10PM +0200, Peter Zijlstra wrote: > From: Oleg Nesterov <o...@redhat.com> > > It would be nice to validate that the caller of rcu_sync_is_idle() > holds the corresponding type of RCU read-side lock. Add the new > rcu_sync_ops->held() method and change rcu_sync_is_idle() to > WARN() if it returns false. > > This obviously penalizes the readers (fast-path), but only if > CONFIG_PROVE_RCU. > > Suggested-by: "Paul E. McKenney" <paul...@linux.vnet.ibm.com> > Signed-off-by: Oleg Nesterov <o...@redhat.com> > Signed-off-by: Peter Zijlstra <pet...@infradead.org>
Reviewed-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> > Link: http://lkml.kernel.org/r/20131004184633.ga17...@redhat.com > --- > include/linux/rcusync.h | 6 ++++++ > kernel/rcusync.c | 21 +++++++++++++++++++++ > 2 files changed, 27 insertions(+) > > --- a/include/linux/rcusync.h > +++ b/include/linux/rcusync.h > @@ -17,9 +17,15 @@ struct rcu_sync_struct { > enum rcu_sync_type gp_type; > }; > > +extern bool __rcu_sync_is_idle(struct rcu_sync_struct *); > + > static inline bool rcu_sync_is_idle(struct rcu_sync_struct *rss) > { > +#ifdef CONFIG_PROVE_RCU > + return __rcu_sync_is_idle(rss); > +#else > return !rss->gp_state; /* GP_IDLE */ > +#endif > } > > extern void rcu_sync_init(struct rcu_sync_struct *, enum rcu_sync_type); > --- a/kernel/rcusync.c > +++ b/kernel/rcusync.c > @@ -1,21 +1,33 @@ > #include <linux/rcusync.h> > #include <linux/sched.h> > > +#ifdef CONFIG_PROVE_RCU > +#define __INIT_HELD(func) .held = func, > +#else > +#define __INIT_HELD(func) > +#endif > + > static const struct { > void (*sync)(void); > void (*call)(struct rcu_head *, void (*)(struct rcu_head *)); > +#ifdef CONFIG_PROVE_RCU > + int (*held)(void); > +#endif > } gp_ops[] = { > [RCU_SYNC] = { > .sync = synchronize_rcu, > .call = call_rcu, > + __INIT_HELD(rcu_read_lock_held) > }, > [RCU_SCHED_SYNC] = { > .sync = synchronize_sched, > .call = call_rcu_sched, > + __INIT_HELD(rcu_read_lock_sched_held) > }, > [RCU_BH_SYNC] = { > .sync = synchronize_rcu_bh, > .call = call_rcu_bh, > + __INIT_HELD(rcu_read_lock_bh_held) > }, > }; > > @@ -24,6 +36,15 @@ enum { CB_IDLE = 0, CB_PENDING, CB_REPLA > > #define rss_lock gp_wait.lock > > +#ifdef CONFIG_PROVE_RCU > +bool __rcu_sync_is_idle(struct rcu_sync_struct *rss) > +{ > + WARN_ON(!gp_ops[rss->gp_type].held()); > + return rss->gp_state == GP_IDLE; > +} > +EXPORT_SYMBOL_GPL(__rcu_sync_is_idle); > +#endif > + > void rcu_sync_init(struct rcu_sync_struct *rss, enum rcu_sync_type type) > { > memset(rss, 0, sizeof(*rss)); > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
