From e2336f6e51edda875a49770b616ed5b02a74665b Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 8 Oct 2014 20:33:48 +0200 Subject: [PATCH] sched: Kill task_preempt_count() task_preempt_count() is pointless if preemption counter is per-cpu, currently this is x86 only. It is only valid if the task is not running, and even in this case the only info it can provide is the state of PREEMPT_ACTIVE bit. Change its single caller to check p->on_rq instead, this should be the same if p->state != TASK_RUNNING, and kill this helper. Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Cc: Steven Rostedt Cc: Kirill Tkhai Cc: Alexander Graf Cc: Andrew Morton Cc: Arnd Bergmann Cc: Christoph Lameter Cc: Linus Torvalds Cc: linux-arch@vger.kernel.org Link: http://lkml.kernel.org/r/20141008183348.GC17495@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/preempt.h | 3 --- include/asm-generic/preempt.h | 3 --- kernel/sched/core.c | 2 +- 3 files changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h index 400873450e33..8f3271842533 100644 --- a/arch/x86/include/asm/preempt.h +++ b/arch/x86/include/asm/preempt.h @@ -30,9 +30,6 @@ static __always_inline void preempt_count_set(int pc) /* * must be macros to avoid header recursion hell */ -#define task_preempt_count(p) \ - (task_thread_info(p)->saved_preempt_count & ~PREEMPT_NEED_RESCHED) - #define init_task_preempt_count(p) do { \ task_thread_info(p)->saved_preempt_count = PREEMPT_DISABLED; \ } while (0) diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h index 1cd3f5d767a8..eb6f9e6c3075 100644 --- a/include/asm-generic/preempt.h +++ b/include/asm-generic/preempt.h @@ -23,9 +23,6 @@ static __always_inline void preempt_count_set(int pc) /* * must be macros to avoid header recursion hell */ -#define task_preempt_count(p) \ - (task_thread_info(p)->preempt_count & ~PREEMPT_NEED_RESCHED) - #define init_task_preempt_count(p) do { \ task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \ } while (0) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 1b69603c1d3e..5c067fd66db9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1054,7 +1054,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) * ttwu() will sort out the placement. */ WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && - !(task_preempt_count(p) & PREEMPT_ACTIVE)); + !p->on_rq); #ifdef CONFIG_LOCKDEP /*