From 80d02085d99039b3b7f3a73c8896226b0cb1ba07 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 12 May 2011 01:08:07 -0700 Subject: Revert "rcu: Decrease memory-barrier usage based on semi-formal proof" This reverts commit e59fb3120becfb36b22ddb8bd27d065d3cdca499. This reversion was due to (extreme) boot-time slowdowns on SPARC seen by Yinghai Lu and on x86 by Ingo . This is a non-trivial reversion due to intervening commits. Conflicts: Documentation/RCU/trace.txt kernel/rcutree.c Signed-off-by: Ingo Molnar --- kernel/rcutree.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'kernel/rcutree.h') diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 93d4a1c..2576648 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -84,9 +84,11 @@ * Dynticks per-CPU state. */ struct rcu_dynticks { - int dynticks_nesting; /* Track irq/process nesting level. */ - int dynticks_nmi_nesting; /* Track NMI nesting level. */ - atomic_t dynticks; /* Even value for dynticks-idle, else odd. */ + int dynticks_nesting; /* Track nesting level, sort of. */ + int dynticks; /* Even value for dynticks-idle, else odd. */ + int dynticks_nmi; /* Even value for either dynticks-idle or */ + /* not in nmi handler, else odd. So this */ + /* remains even for nmi from irq handler. */ }; /* RCU's kthread states for tracing. */ @@ -282,6 +284,7 @@ struct rcu_data { /* 3) dynticks interface. */ struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */ int dynticks_snap; /* Per-GP tracking for dynticks. */ + int dynticks_nmi_snap; /* Per-GP tracking for dynticks_nmi. */ #endif /* #ifdef CONFIG_NO_HZ */ /* 4) reasons this CPU needed to be kicked by force_quiescent_state */ -- cgit v1.1