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| author | Peter Zijlstra <peterz@infradead.org> | 2014-09-23 17:06:41 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-09-24 14:47:05 +0200 |
| commit | c55f5158f5606f8a62e694b7e009f59b92ac6258 (patch) | |
| tree | f51365aca7822ecf82a03c65c919b84274ff86a2 /kernel/sched/sched.h | |
| parent | sched: print_rq(): Don't use tasklist_lock (diff) | |
| download | linux-c55f5158f5606f8a62e694b7e009f59b92ac6258.tar.xz linux-c55f5158f5606f8a62e694b7e009f59b92ac6258.zip | |
sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW
Kirill found that there's a subtle race in the
__ARCH_WANT_UNLOCKED_CTXSW code, and instead of fixing it, remove the
entire exception because neither arch that uses it seems to actually
still require it.
Boot tested on mips64el (qemu) only.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kirill Tkhai <tkhai@yandex.ru>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: oleg@redhat.com
Cc: linux@roeck-us.net
Cc: linux-ia64@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20140923150641.GH3312@worktop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/sched.h')
| -rw-r--r-- | kernel/sched/sched.h | 30 |
1 files changed, 0 insertions, 30 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 16e1ca9cb7e8..6130251de280 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -975,7 +975,6 @@ static inline int task_on_rq_migrating(struct task_struct *p) # define finish_arch_post_lock_switch() do { } while (0) #endif -#ifndef __ARCH_WANT_UNLOCKED_CTXSW static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) { #ifdef CONFIG_SMP @@ -1013,35 +1012,6 @@ static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) raw_spin_unlock_irq(&rq->lock); } -#else /* __ARCH_WANT_UNLOCKED_CTXSW */ -static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) -{ -#ifdef CONFIG_SMP - /* - * We can optimise this out completely for !SMP, because the - * SMP rebalancing from interrupt is the only thing that cares - * here. - */ - next->on_cpu = 1; -#endif - raw_spin_unlock(&rq->lock); -} - -static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) -{ -#ifdef CONFIG_SMP - /* - * After ->on_cpu is cleared, the task can be moved to a different CPU. - * We must ensure this doesn't happen until the switch is completely - * finished. - */ - smp_wmb(); - prev->on_cpu = 0; -#endif - local_irq_enable(); -} -#endif /* __ARCH_WANT_UNLOCKED_CTXSW */ - /* * wake flags */ |