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Commit 11992c70 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Remove CONFIG_PROVE_RCU_DELAY 



The CONFIG_PROVE_RCU_DELAY Kconfig parameter doesn't appear to be very
effective at finding race conditions, so this commit removes it.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
[ paulmck: Remove definition and uses as noted by Paul Bolle. ]
parent d860d403

kernel/rcu/tree.c

+0 −5
Original line number Diff line number Diff line
@@ -1647,11 +1647,6 @@ static int rcu_gp_init(struct rcu_state *rsp) 
					    rnp->level, rnp->grplo,

					    rnp->grphi, rnp->qsmask);

		raw_spin_unlock_irq(&rnp->lock);

#ifdef CONFIG_PROVE_RCU_DELAY

		if ((prandom_u32() % (rcu_num_nodes + 1)) == 0 &&

		    system_state == SYSTEM_RUNNING)

			udelay(200);

#endif /* #ifdef CONFIG_PROVE_RCU_DELAY */

		cond_resched();

	}

kernel/rcu/update.c

+0 −3
Original line number Diff line number Diff line
@@ -90,9 +90,6 @@ void __rcu_read_unlock(void) 
	} else {

		barrier();  /* critical section before exit code. */

		t->rcu_read_lock_nesting = INT_MIN;

#ifdef CONFIG_PROVE_RCU_DELAY

		udelay(10); /* Make preemption more probable. */

#endif /* #ifdef CONFIG_PROVE_RCU_DELAY */

		barrier();  /* assign before ->rcu_read_unlock_special load */

		if (unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))

			rcu_read_unlock_special(t);

lib/Kconfig.debug

+0 −14
Original line number Diff line number Diff line
@@ -1131,20 +1131,6 @@ config PROVE_RCU_REPEATEDLY 


	 Say N if you are unsure.



config PROVE_RCU_DELAY

	bool "RCU debugging: preemptible RCU race provocation"

	depends on DEBUG_KERNEL && PREEMPT_RCU

	default n

	help

	 There is a class of races that involve an unlikely preemption

	 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has

	 been set to INT_MIN.  This feature inserts a delay at that

	 point to increase the probability of these races.



	 Say Y to increase probability of preemption of __rcu_read_unlock().



	 Say N if you are unsure.



config SPARSE_RCU_POINTER

	bool "RCU debugging: sparse-based checks for pointer usage"

	default n

tools/testing/selftests/rcutorture/configs/rcu/TREE01

+0 −1
Original line number Diff line number Diff line
@@ -15,7 +15,6 @@ CONFIG_RCU_FANOUT_EXACT=n 
CONFIG_RCU_NOCB_CPU=y

CONFIG_RCU_NOCB_CPU_ZERO=y

CONFIG_DEBUG_LOCK_ALLOC=n

CONFIG_PROVE_RCU_DELAY=n

CONFIG_RCU_CPU_STALL_INFO=n

CONFIG_RCU_CPU_STALL_VERBOSE=n

CONFIG_RCU_BOOST=n

tools/testing/selftests/rcutorture/configs/rcu/TREE02

+0 −1
Original line number Diff line number Diff line
@@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_EXACT=n 
CONFIG_RCU_NOCB_CPU=n

CONFIG_DEBUG_LOCK_ALLOC=y

CONFIG_PROVE_LOCKING=n

CONFIG_PROVE_RCU_DELAY=n

CONFIG_RCU_CPU_STALL_INFO=n

CONFIG_RCU_CPU_STALL_VERBOSE=y

CONFIG_RCU_BOOST=n