Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 1/2] irq: Remove IRQ_EXIT_OFFSET workaround | Date | Fri, 22 Feb 2013 02:36:10 +0100 |
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The IRQ_EXIT_OFFSET trick was used to make sure the irq doesn't get preempted after we substract the HARDIRQ_OFFSET until we are entirely done with any code in irq_exit().
This workaround was necessary because some archs may call irq_exit() with irqs enabled and there is still some code in the end of this function that is not covered by the HARDIRQ_OFFSET but want to stay non-preemptible.
Now that irq are always disabled in irq_exit(), the whole code is guaranteed not to be preempted. We can thus remove this hack.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- include/linux/hardirq.h | 2 -- kernel/softirq.c | 3 +-- 2 files changed, 1 insertions(+), 4 deletions(-)
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index 29eb805..c1d6555 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -118,10 +118,8 @@ #ifdef CONFIG_PREEMPT_COUNT # define preemptible() (preempt_count() == 0 && !irqs_disabled()) -# define IRQ_EXIT_OFFSET (HARDIRQ_OFFSET-1) #else # define preemptible() 0 -# define IRQ_EXIT_OFFSET HARDIRQ_OFFSET #endif #if defined(CONFIG_SMP) || defined(CONFIG_GENERIC_HARDIRQS) diff --git a/kernel/softirq.c b/kernel/softirq.c index 24a921b..f42ff97 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -343,7 +343,7 @@ void irq_exit(void) account_irq_exit_time(current); trace_hardirq_exit(); - sub_preempt_count(IRQ_EXIT_OFFSET); + sub_preempt_count(HARDIRQ_OFFSET); if (!in_interrupt() && local_softirq_pending()) invoke_softirq(); @@ -353,7 +353,6 @@ void irq_exit(void) tick_nohz_irq_exit(); #endif rcu_irq_exit(); - sched_preempt_enable_no_resched(); #ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED local_irq_restore(flags); #endif -- 1.7.5.4
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