From c5a3f2e9981b6da91e70765d0a958a0ac9d14a53 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 24 Aug 2012 13:22:13 -0700 Subject: [PATCH] ia64: Add missing RCU idle APIs on idle loop commit 93482f4ef1093f5961a63359a34612183d6beea0 upstream. Traditionally, the entire idle task served as an RCU quiescent state. But when RCU read side critical sections started appearing within the idle loop, this traditional strategy became untenable. The fix was to create new RCU APIs named rcu_idle_enter() and rcu_idle_exit(), which must be called by each architecture's idle loop so that RCU can tell when it is safe to ignore a given idle CPU. Unfortunately, this fix was never applied to ia64, a shortcoming remedied by this commit. Reported by: Tony Luck Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Tested by: Tony Luck Reviewed-by: Josh Triplett Signed-off-by: Greg Kroah-Hartman --- arch/ia64/kernel/process.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c index ce74e14..86d74ab 100644 --- a/arch/ia64/kernel/process.c +++ b/arch/ia64/kernel/process.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include @@ -301,6 +302,7 @@ cpu_idle (void) /* endless idle loop with no priority at all */ while (1) { + rcu_idle_enter(); if (can_do_pal_halt) { current_thread_info()->status &= ~TS_POLLING; /* @@ -331,6 +333,7 @@ cpu_idle (void) normal_xtp(); #endif } + rcu_idle_exit(); schedule_preempt_disabled(); check_pgt_cache(); if (cpu_is_offline(cpu)) -- 2.7.4