From febdbfe8a91ce0d11939d4940b592eb0dba8d663 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 6 Feb 2014 18:16:07 +0100 Subject: arch: Prepare for smp_mb__{before,after}_atomic() Since the smp_mb__{before,after}*() ops are fundamentally dependent on how an arch can implement atomics it doesn't make sense to have 3 variants of them. They must all be the same. Furthermore, the 3 variants suggest they're only valid for those 3 atomic ops, while we have many more where they could be applied. So move away from smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}() and reduce the interface to just the two: smp_mb__{before,after}_atomic(). This patch prepares the way by introducing default implementations in asm-generic/barrier.h that default to a full barrier and providing __deprecated inlines for the previous 6 barriers if they're not provided by the arch. This should allow for a mostly painless transition (lots of deprecated warns in the interim). Signed-off-by: Peter Zijlstra Acked-by: Paul E. McKenney Link: http://lkml.kernel.org/n/tip-wr59327qdyi9mbzn6x937s4e@git.kernel.org Cc: Arnd Bergmann Cc: "Chen, Gong" Cc: John Sullivan Cc: Linus Torvalds Cc: Mauro Carvalho Chehab Cc: Srinivas Pandruvada Cc: "Theodore Ts'o" Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel/sched') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 268a45ea238c..8a70ec091760 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -90,6 +90,22 @@ #define CREATE_TRACE_POINTS #include +#ifdef smp_mb__before_atomic +void __smp_mb__before_atomic(void) +{ + smp_mb__before_atomic(); +} +EXPORT_SYMBOL(__smp_mb__before_atomic); +#endif + +#ifdef smp_mb__after_atomic +void __smp_mb__after_atomic(void) +{ + smp_mb__after_atomic(); +} +EXPORT_SYMBOL(__smp_mb__after_atomic); +#endif + void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) { unsigned long delta; -- cgit v1.2.3 From 4e857c58efeb99393cba5a5d0d8ec7117183137c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 17 Mar 2014 18:06:10 +0100 Subject: arch: Mass conversion of smp_mb__*() Mostly scripted conversion of the smp_mb__* barriers. Signed-off-by: Peter Zijlstra Acked-by: Paul E. McKenney Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org Cc: Linus Torvalds Cc: linux-arch@vger.kernel.org Signed-off-by: Ingo Molnar --- kernel/sched/cpupri.c | 6 +++--- kernel/sched/wait.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c index 8b836b376d91..746bc9344969 100644 --- a/kernel/sched/cpupri.c +++ b/kernel/sched/cpupri.c @@ -165,7 +165,7 @@ void cpupri_set(struct cpupri *cp, int cpu, int newpri) * do a write memory barrier, and then update the count, to * make sure the vector is visible when count is set. */ - smp_mb__before_atomic_inc(); + smp_mb__before_atomic(); atomic_inc(&(vec)->count); do_mb = 1; } @@ -185,14 +185,14 @@ void cpupri_set(struct cpupri *cp, int cpu, int newpri) * the new priority vec. */ if (do_mb) - smp_mb__after_atomic_inc(); + smp_mb__after_atomic(); /* * When removing from the vector, we decrement the counter first * do a memory barrier and then clear the mask. */ atomic_dec(&(vec)->count); - smp_mb__after_atomic_inc(); + smp_mb__after_atomic(); cpumask_clear_cpu(cpu, vec->mask); } diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 7d50f794e248..0ffa20ae657b 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -394,7 +394,7 @@ EXPORT_SYMBOL(__wake_up_bit); * * In order for this to function properly, as it uses waitqueue_active() * internally, some kind of memory barrier must be done prior to calling - * this. Typically, this will be smp_mb__after_clear_bit(), but in some + * this. Typically, this will be smp_mb__after_atomic(), but in some * cases where bitflags are manipulated non-atomically under a lock, one * may need to use a less regular barrier, such fs/inode.c's smp_mb(), * because spin_unlock() does not guarantee a memory barrier. -- cgit v1.2.3