From 43858b4f25cf0adc5c2ca9cf5ce5fdf2532941e5 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 29 Jun 2017 08:53:18 -0700 Subject: x86/mm: Stop calling leave_mm() in idle code Now that lazy TLB suppresses all flush IPIs (as opposed to all but the first), there's no need to leave_mm() when going idle. This means we can get rid of the rcuidle hack in switch_mm_irqs_off() and we can unexport leave_mm(). This also removes acpi_unlazy_tlb() from the x86 and ia64 headers, since it has no callers any more. Signed-off-by: Andy Lutomirski Reviewed-by: Nadav Amit Reviewed-by: Borislav Petkov Reviewed-by: Thomas Gleixner Cc: Andrew Morton Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dave Hansen Cc: Linus Torvalds Cc: Mel Gorman Cc: Peter Zijlstra Cc: Rik van Riel Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/03c699cfd6021e467be650d6b73deaccfe4b4bd7.1498751203.git.luto@kernel.org Signed-off-by: Ingo Molnar --- drivers/idle/intel_idle.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'drivers/idle') diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 216d7ec88c0c..2ae43f59091d 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -912,16 +912,15 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state = &drv->states[index]; unsigned long eax = flg2MWAIT(state->flags); unsigned int cstate; - int cpu = smp_processor_id(); cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1; /* - * leave_mm() to avoid costly and often unnecessary wakeups - * for flushing the user TLB's associated with the active mm. + * NB: if CPUIDLE_FLAG_TLB_FLUSHED is set, this idle transition + * will probably flush the TLB. It's not guaranteed to flush + * the TLB, though, so it's not clear that we can do anything + * useful with this knowledge. */ - if (state->flags & CPUIDLE_FLAG_TLB_FLUSHED) - leave_mm(cpu); if (!(lapic_timer_reliable_states & (1 << (cstate)))) tick_broadcast_enter(); -- cgit v1.2.3