Messages in this thread Patch in this message | | | From | Sebastian Andrzej Siewior <> | Subject | [PATCH 1/2] x86/entry: Use should_resched() in idtentry_exit_cond_resched() | Date | Tue, 30 Jun 2020 12:22:08 +0200 |
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The TIF_NEED_RESCHED bit is inlined on x86 into the preemption counter. So instead checking the preemption counter against zero via preempt_count() and later checking the TIF_NEED_RESCHED bit via need_resched() we could use should_resched() which does both checks in one go. The functional difference is that we don't enter the if statement with preempt_count == 0 and TIF_NEED_RESCHED not set.
Use should_resched() instead need_resched() + preempt_count().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- arch/x86/entry/common.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index bd3f14175193c..212382f61b8e4 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -612,13 +612,12 @@ bool noinstr idtentry_enter_cond_rcu(struct pt_regs *regs) static void idtentry_exit_cond_resched(struct pt_regs *regs, bool may_sched) { - if (may_sched && !preempt_count()) { + if (may_sched && should_resched(0)) { /* Sanity check RCU and thread stack */ rcu_irq_exit_check_preempt(); if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) WARN_ON_ONCE(!on_thread_stack()); - if (need_resched()) - preempt_schedule_irq(); + preempt_schedule_irq(); } /* Covers both tracing and lockdep */ trace_hardirqs_on(); -- 2.27.0
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