From 11992c703a1c7d95f5d8759498d7617d4a504819 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 23 Jun 2014 12:09:52 -0700 Subject: [PATCH] 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: Paul E. McKenney Cc: Andi Kleen [ paulmck: Remove definition and uses as noted by Paul Bolle. ] --- kernel/rcu/tree.c | 5 ----- kernel/rcu/update.c | 3 --- lib/Kconfig.debug | 14 -------------- .../selftests/rcutorture/configs/rcu/TREE01 | 1 - .../selftests/rcutorture/configs/rcu/TREE02 | 1 - .../selftests/rcutorture/configs/rcu/TREE02-T | 1 - .../selftests/rcutorture/configs/rcu/TREE03 | 1 - .../selftests/rcutorture/configs/rcu/TREE04 | 1 - .../selftests/rcutorture/configs/rcu/TREE05 | 1 - .../selftests/rcutorture/configs/rcu/TREE06 | 1 - .../selftests/rcutorture/configs/rcu/TREE07 | 1 - .../selftests/rcutorture/configs/rcu/TREE08 | 1 - .../selftests/rcutorture/configs/rcu/TREE08-T | 1 - .../selftests/rcutorture/configs/rcu/TREE09 | 1 - .../configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp | 1 - .../configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp | 1 - .../configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp | 1 - .../configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp | 1 - .../selftests/rcutorture/doc/TREE_RCU-kconfig.txt | 1 - 19 files changed, 38 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index a6c5424ffa38..1b70cb6fbe3c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -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(); } diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index bc7883570530..4056d7992a6c 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -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); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 7cfcc1b8e101..4c37d5459b41 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -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 diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE01 b/tools/testing/selftests/rcutorture/configs/rcu/TREE01 index 9c827ec59a97..063b7079c621 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE01 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE01 @@ -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 diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02 b/tools/testing/selftests/rcutorture/configs/rcu/TREE02 index 1a777b5f68b5..ea119ba2f7d4 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE02 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE02 @@ -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 diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T index 61c8d9ce5bb2..19cf9485f48a 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE02-T @@ -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 diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE03 b/tools/testing/selftests/rcutorture/configs/rcu/TREE03 index c1f111c1561b..f4567fb3e332 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE03 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE03 @@ -14,7 +14,6 @@ CONFIG_RCU_FANOUT_LEAF=4 CONFIG_RCU_FANOUT_EXACT=n CONFIG_RCU_NOCB_CPU=n 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=y diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE04 b/tools/testing/selftests/rcutorture/configs/rcu/TREE04 index 7dbd27ce17a4..0a262fbb0c12 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE04 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE04 @@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_LEAF=2 CONFIG_RCU_FANOUT_EXACT=n CONFIG_RCU_NOCB_CPU=n CONFIG_DEBUG_LOCK_ALLOC=n -CONFIG_PROVE_RCU_DELAY=n CONFIG_RCU_CPU_STALL_INFO=y CONFIG_RCU_CPU_STALL_VERBOSE=y CONFIG_DEBUG_OBJECTS_RCU_HEAD=n diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE05 b/tools/testing/selftests/rcutorture/configs/rcu/TREE05 index d0f32e574743..3a06b97e9a73 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE05 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE05 @@ -18,7 +18,6 @@ CONFIG_RCU_NOCB_CPU_NONE=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_PROVE_RCU=y -CONFIG_PROVE_RCU_DELAY=y CONFIG_RCU_CPU_STALL_INFO=n CONFIG_RCU_CPU_STALL_VERBOSE=n CONFIG_DEBUG_OBJECTS_RCU_HEAD=n diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE06 b/tools/testing/selftests/rcutorture/configs/rcu/TREE06 index 2e477dfb9c57..8f084cca91bf 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE06 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE06 @@ -19,7 +19,6 @@ CONFIG_RCU_NOCB_CPU=n CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_PROVE_RCU=y -CONFIG_PROVE_RCU_DELAY=n CONFIG_RCU_CPU_STALL_INFO=n CONFIG_RCU_CPU_STALL_VERBOSE=n CONFIG_DEBUG_OBJECTS_RCU_HEAD=y diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE07 b/tools/testing/selftests/rcutorture/configs/rcu/TREE07 index 042f86ef362a..ab6225506909 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE07 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE07 @@ -17,7 +17,6 @@ CONFIG_RCU_FANOUT_LEAF=2 CONFIG_RCU_FANOUT_EXACT=n CONFIG_RCU_NOCB_CPU=n CONFIG_DEBUG_LOCK_ALLOC=n -CONFIG_PROVE_RCU_DELAY=n CONFIG_RCU_CPU_STALL_INFO=y CONFIG_RCU_CPU_STALL_VERBOSE=n CONFIG_DEBUG_OBJECTS_RCU_HEAD=n diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08 b/tools/testing/selftests/rcutorture/configs/rcu/TREE08 index 3438cee1e3c5..69a2e255bf98 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE08 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE08 @@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_LEAF=2 CONFIG_RCU_NOCB_CPU=y CONFIG_RCU_NOCB_CPU_ALL=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 diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T b/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T index bf4523d3e44c..a0f32fb8f17e 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE08-T @@ -18,7 +18,6 @@ CONFIG_RCU_FANOUT_LEAF=2 CONFIG_RCU_NOCB_CPU=y CONFIG_RCU_NOCB_CPU_ALL=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 diff --git a/tools/testing/selftests/rcutorture/configs/rcu/TREE09 b/tools/testing/selftests/rcutorture/configs/rcu/TREE09 index 81e4f7c0bf0b..b7a62a540ad1 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/TREE09 +++ b/tools/testing/selftests/rcutorture/configs/rcu/TREE09 @@ -13,7 +13,6 @@ CONFIG_SUSPEND=n CONFIG_HIBERNATION=n CONFIG_RCU_NOCB_CPU=n 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 diff --git a/tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp b/tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp index ef624ce73d8e..a55c00877fe4 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp +++ b/tools/testing/selftests/rcutorture/configs/rcu/v0.0/P5-U-T-NH-sd-SMP-hp @@ -13,7 +13,6 @@ CONFIG_PREEMPT_VOLUNTARY=n CONFIG_PREEMPT=y #CHECK#CONFIG_TREE_PREEMPT_RCU=y CONFIG_DEBUG_KERNEL=y -CONFIG_PROVE_RCU_DELAY=y CONFIG_DEBUG_OBJECTS=y CONFIG_DEBUG_OBJECTS_RCU_HEAD=y CONFIG_RT_MUTEXES=y diff --git a/tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp b/tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp index ef624ce73d8e..a55c00877fe4 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp +++ b/tools/testing/selftests/rcutorture/configs/rcu/v3.12/P5-U-T-NH-sd-SMP-hp @@ -13,7 +13,6 @@ CONFIG_PREEMPT_VOLUNTARY=n CONFIG_PREEMPT=y #CHECK#CONFIG_TREE_PREEMPT_RCU=y CONFIG_DEBUG_KERNEL=y -CONFIG_PROVE_RCU_DELAY=y CONFIG_DEBUG_OBJECTS=y CONFIG_DEBUG_OBJECTS_RCU_HEAD=y CONFIG_RT_MUTEXES=y diff --git a/tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp b/tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp index ef624ce73d8e..a55c00877fe4 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp +++ b/tools/testing/selftests/rcutorture/configs/rcu/v3.3/P5-U-T-NH-sd-SMP-hp @@ -13,7 +13,6 @@ CONFIG_PREEMPT_VOLUNTARY=n CONFIG_PREEMPT=y #CHECK#CONFIG_TREE_PREEMPT_RCU=y CONFIG_DEBUG_KERNEL=y -CONFIG_PROVE_RCU_DELAY=y CONFIG_DEBUG_OBJECTS=y CONFIG_DEBUG_OBJECTS_RCU_HEAD=y CONFIG_RT_MUTEXES=y diff --git a/tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp b/tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp index ef624ce73d8e..a55c00877fe4 100644 --- a/tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp +++ b/tools/testing/selftests/rcutorture/configs/rcu/v3.5/P5-U-T-NH-sd-SMP-hp @@ -13,7 +13,6 @@ CONFIG_PREEMPT_VOLUNTARY=n CONFIG_PREEMPT=y #CHECK#CONFIG_TREE_PREEMPT_RCU=y CONFIG_DEBUG_KERNEL=y -CONFIG_PROVE_RCU_DELAY=y CONFIG_DEBUG_OBJECTS=y CONFIG_DEBUG_OBJECTS_RCU_HEAD=y CONFIG_RT_MUTEXES=y diff --git a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt index adbb76cffb49..3e588db86a17 100644 --- a/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt +++ b/tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt @@ -14,7 +14,6 @@ CONFIG_NO_HZ_FULL_SYSIDLE -- Do one. CONFIG_PREEMPT -- Do half. (First three and #8.) CONFIG_PROVE_LOCKING -- Do all but two, covering CONFIG_PROVE_RCU and not. CONFIG_PROVE_RCU -- Do all but one under CONFIG_PROVE_LOCKING. -CONFIG_PROVE_RCU_DELAY -- Do one. CONFIG_RCU_BOOST -- one of TREE_PREEMPT_RCU. CONFIG_RCU_BOOST_PRIO -- set to 2 for _BOOST testing. CONFIG_RCU_CPU_STALL_INFO -- do one with and without _VERBOSE. -- 2.39.5