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Groups > linux.kernel > #1626570
| From | "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v3 tip/core/rcu 12/40] rcu: Default RCU_FANOUT_LEAF to 16 unless explicitly changed |
| Date | 2017-04-19 19:00 +0200 |
| Message-ID | <ty17t-5PA-71@gated-at.bofh.it> (permalink) |
| References | <ty17r-5PA-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
If the RCU_EXPERT Kconfig option is not set (the default), then the RCU_FANOUT_LEAF Kconfig option will not be defined, which will cause the leaf-level rcu_node tree fanout to default to 32 on 32-bit systems and 64 on 64-bit systems. This can result in excessive lock contention. This commit therefore changes the computation of the leaf-level rcu_node tree fanout so that the result will be 16 unless an explicit Kconfig or kernel-boot setting says otherwise. Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- kernel/rcu/tree.h | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index d2f276fc2edc..376c01e539c7 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -52,11 +52,7 @@ #ifdef CONFIG_RCU_FANOUT_LEAF #define RCU_FANOUT_LEAF CONFIG_RCU_FANOUT_LEAF #else /* #ifdef CONFIG_RCU_FANOUT_LEAF */ -# ifdef CONFIG_64BIT -# define RCU_FANOUT_LEAF 64 -# else -# define RCU_FANOUT_LEAF 32 -# endif +#define RCU_FANOUT_LEAF 16 #endif /* #else #ifdef CONFIG_RCU_FANOUT_LEAF */ #define RCU_FANOUT_1 (RCU_FANOUT_LEAF) -- 2.5.2
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[PATCH tip/core/rcu 0/40] SRCU callback parallelization for 4.12 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-12 19:50 +0200
[PATCH tip/core/rcu 03/40] srcu: Consolidate batch checking into rcu_all_batches_empty() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-12 20:00 +0200
[PATCH tip/core/rcu 05/40] rcu: Semicolon inside RCU_TRACE() for rcu.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-12 20:00 +0200
[PATCH tip/core/rcu 11/40] rcu: Pull rcu_sched_qs_mask into rcu_dynticks structure "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-12 20:00 +0200
Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling Peter Zijlstra <peterz@infradead.org> - 2017-04-13 12:00 +0200
Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-13 18:40 +0200
Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-13 19:50 +0200
Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling Peter Zijlstra <peterz@infradead.org> - 2017-04-13 12:00 +0200
Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-13 19:00 +0200
[PATCH v2 tip/core/rcu 0/40] SRCU callback parallelization for 4.12 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 02/39] rcu: Make arch select smp_mb__after_unlock_lock() strength "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
Re: [PATCH v2 tip/core/rcu 02/39] rcu: Make arch select smp_mb__after_unlock_lock() strength Josh Triplett <josh@joshtriplett.org> - 2017-04-18 02:20 +0200
[PATCH v2 tip/core/rcu 10/39] rcu: Eliminate flavor scan in rcu_momentary_dyntick_idle() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 24/39] srcu: Move combining-tree definitions for SRCU's benefit "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 31/39] srcu: Allow a second bit in rcu_seq for SRCU state "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 15/39] srcu: Allow early boot use of synchronize_srcu() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 14/39] srcu: Allow SRCU to access rcu_scheduler_active "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 05/39] rcu: Semicolon inside RCU_TRACE() for rcu.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 33/39] srcu: Crude control of expedited grace periods "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 29/39] srcu: Fix bogus try_check_zero() comment "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 25/39] srcu: Move rcu_init_levelspread() to rcu_tree_node.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 27/39] srcu: Move rcu_node traversal macros to rcu.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 06/39] rcu: Semicolon inside RCU_TRACE() for Tiny RCU "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 39/39] rcu: Make non-preemptive schedule be Tasks RCU quiescent state "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 07/39] rcu: Semicolon inside RCU_TRACE() for tree.c "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 18/39] rcu: Expedited wakeups need to be fully ordered "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 21/39] srcu: Move to state-based grace-period sequencing "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 22/39] srcu: Add grace-period sequence numbers "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 34/39] mm: Use static initialization for "srcu" "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 35/39] srcu: Create a tiny SRCU "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 16/39] rcu: Add single-element dequeue functions to rcu_segcblist "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 01:50 +0200
[PATCH v2 tip/core/rcu 19/39] rcu: Fix warning in rcu_seq_end() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 03/39] srcu: Consolidate batch checking into rcu_all_batches_empty() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
Re: [PATCH v2 tip/core/rcu 03/39] srcu: Consolidate batch checking into rcu_all_batches_empty() Josh Triplett <josh@joshtriplett.org> - 2017-04-18 02:40 +0200
[PATCH v2 tip/core/rcu 08/39] rcu: Pull rcu_sched_qs_mask into rcu_dynticks structure "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 09/39] rcu: Pull rcu_qs_ctr into rcu_dynticks structure "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 30/39] srcu: Improve rcu_seq grace-period-counter abstraction "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 17/39] srcu: Move rcu_seq_start() and friends to rcu.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 11/39] rcu: Place guard on rcu_all_qs() and rcu_note_context_switch() actions "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 28/39] srcu: Make num_rcu_lvl[] array be external "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 26/39] rcu: Remove redundant levelcnt[] array from rcu_init_one() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 32/39] srcu: Merge ->srcu_state into ->srcu_gp_seq "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 36/39] srcutorture: Print Tiny SRCU reader statistics "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
[PATCH v2 tip/core/rcu 01/39] rcu: Maintain special bits at bottom of ->dynticks counter "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
Re: [PATCH v2 tip/core/rcu 01/39] rcu: Maintain special bits at bottom of ->dynticks counter Josh Triplett <josh@joshtriplett.org> - 2017-04-18 02:10 +0200
Re: [PATCH v2 tip/core/rcu 01/39] rcu: Maintain special bits at bottom of ->dynticks counter "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 20:30 +0200
[PATCH v2 tip/core/rcu 04/39] srcu: Check for tardy grace-period activity in cleanup_srcu_struct() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 02:00 +0200
Re: [PATCH v2 tip/core/rcu 04/39] srcu: Check for tardy grace-period activity in cleanup_srcu_struct() Josh Triplett <josh@joshtriplett.org> - 2017-04-18 02:40 +0200
Re: [PATCH v2 tip/core/rcu 04/39] srcu: Check for tardy grace-period activity in cleanup_srcu_struct() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-18 20:40 +0200
Re: [PATCH v2 tip/core/rcu 04/39] srcu: Check for tardy grace-period activity in cleanup_srcu_struct() Josh Triplett <josh@joshtriplett.org> - 2017-04-18 21:50 +0200
Re: [PATCH v2 tip/core/rcu 04/39] srcu: Check for tardy grace-period activity in cleanup_srcu_struct() Josh Triplett <josh@joshtriplett.org> - 2017-04-18 02:40 +0200
[PATCH v3 tip/core/rcu 0/40] SRCU callback parallelization for 4.12 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:00 +0200
[PATCH v3 tip/core/rcu 35/40] srcu: Create a tiny SRCU "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:00 +0200
[PATCH v3 tip/core/rcu 12/40] rcu: Default RCU_FANOUT_LEAF to 16 unless explicitly changed "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:00 +0200
[PATCH v3 tip/core/rcu 05/40] rcu: Semicolon inside RCU_TRACE() for rcu.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
Re: [PATCH v3 tip/core/rcu 05/40] rcu: Semicolon inside RCU_TRACE() for rcu.h Joe Perches <joe@perches.com> - 2017-04-19 19:50 +0200
[PATCH v3 tip/core/rcu 26/40] rcu: Remove redundant levelcnt[] array from rcu_init_one() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 14/40] srcu: Allow SRCU to access rcu_scheduler_active "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 27/40] srcu: Move rcu_node traversal macros to rcu.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 19/40] rcu: Fix warning in rcu_seq_end() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 29/40] srcu: Fix bogus try_check_zero() comment "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 28/40] srcu: Make num_rcu_lvl[] array be external "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 22/40] srcu: Add grace-period sequence numbers "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 39/40] srcu: Expedite srcu_schedule_cbs_snp() callback invocation "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 30/40] srcu: Improve rcu_seq grace-period-counter abstraction "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 01/40] rcu: Maintain special bits at bottom of ->dynticks counter "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 20/40] srcu: Push srcu_advance_batches() fastpath into common case "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 34/40] mm: Use static initialization for "srcu" "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 17/40] srcu: Move rcu_seq_start() and friends to rcu.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 08/40] rcu: Pull rcu_sched_qs_mask into rcu_dynticks structure "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 36/40] srcutorture: Print Tiny SRCU reader statistics "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 09/40] rcu: Pull rcu_qs_ctr into rcu_dynticks structure "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 04/40] srcu: Check for tardy grace-period activity in cleanup_srcu_struct() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 07/40] rcu: Semicolon inside RCU_TRACE() for tree.c "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 10/40] rcu: Eliminate flavor scan in rcu_momentary_dyntick_idle() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 02/40] rcu: Make arch select smp_mb__after_unlock_lock() strength "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 24/40] srcu: Move combining-tree definitions for SRCU's benefit "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 15/40] srcu: Allow early boot use of synchronize_srcu() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 33/40] srcu: Crude control of expedited grace periods "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 06/40] rcu: Semicolon inside RCU_TRACE() for Tiny RCU "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 03/40] srcu: Consolidate batch checking into rcu_all_batches_empty() "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 32/40] srcu: Merge ->srcu_state into ->srcu_gp_seq "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
[PATCH v3 tip/core/rcu 25/40] srcu: Move rcu_init_levelspread() to rcu_tree_node.h "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-19 19:10 +0200
powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) Michael Ellerman <michaele@au1.ibm.com> - 2017-04-20 05:50 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-20 16:30 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) Paolo Bonzini <pbonzini@redhat.com> - 2017-04-20 17:30 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-21 02:40 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) Michael Ellerman <michaele@au1.ibm.com> - 2017-04-21 03:50 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-21 06:20 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) Paolo Bonzini <pbonzini@redhat.com> - 2017-04-21 09:30 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-21 15:00 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) Michael Ellerman <michaele@au1.ibm.com> - 2017-04-22 08:20 +0200
Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) Michael Ellerman <michaele@au1.ibm.com> - 2017-04-21 04:20 +0200
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