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[198.145.29.99]) by mx.google.com with ESMTPS id i22si3170578oib.289.2017.06.05.15.37.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Jun 2017 15:37:09 -0700 (PDT) From: Andy Lutomirski Subject: [RFC 06/11] x86/mm: Stop calling leave_mm() in idle code Date: Mon, 5 Jun 2017 15:36:30 -0700 Message-Id: In-Reply-To: References: In-Reply-To: References: Sender: owner-linux-mm@kvack.org List-ID: To: X86 ML Cc: Borislav Petkov , Linus Torvalds , Andrew Morton , Mel Gorman , "linux-mm@kvack.org" , Nadav Amit , Rik van Riel , Andy Lutomirski 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 --- arch/ia64/include/asm/acpi.h | 2 -- arch/x86/include/asm/acpi.h | 2 -- arch/x86/mm/tlb.c | 19 +++---------------- drivers/acpi/processor_idle.c | 2 -- drivers/idle/intel_idle.c | 8 ++++---- 5 files changed, 7 insertions(+), 26 deletions(-) diff --git a/arch/ia64/include/asm/acpi.h b/arch/ia64/include/asm/acpi.h index a3d0211970e9..c86a947f5368 100644 --- a/arch/ia64/include/asm/acpi.h +++ b/arch/ia64/include/asm/acpi.h @@ -112,8 +112,6 @@ static inline void arch_acpi_set_pdc_bits(u32 *buf) buf[2] |= ACPI_PDC_EST_CAPABILITY_SMP; } -#define acpi_unlazy_tlb(x) - #ifdef CONFIG_ACPI_NUMA extern cpumask_t early_cpu_possible_map; #define for_each_possible_early_cpu(cpu) \ diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h index 2efc768e4362..562286fa151f 100644 --- a/arch/x86/include/asm/acpi.h +++ b/arch/x86/include/asm/acpi.h @@ -150,8 +150,6 @@ static inline void disable_acpi(void) { } extern int x86_acpi_numa_init(void); #endif /* CONFIG_ACPI_NUMA */ -#define acpi_unlazy_tlb(x) leave_mm(x) - #ifdef CONFIG_ACPI_APEI static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr) { diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 95d71407247a..09775cf5cb1b 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -50,7 +50,6 @@ void leave_mm(int cpu) switch_mm(NULL, &init_mm, NULL); } -EXPORT_SYMBOL_GPL(leave_mm); void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk) @@ -113,14 +112,8 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, this_cpu_write(cpu_tlbstate.ctxs[0].tlb_gen, next_tlb_gen); write_cr3(__pa(next->pgd)); - /* - * This gets called via leave_mm() in the idle path - * where RCU functions differently. Tracing normally - * uses RCU, so we have to call the tracepoint - * specially here. - */ - trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, - TLB_FLUSH_ALL); + trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, + TLB_FLUSH_ALL); } /* @@ -166,13 +159,7 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, this_cpu_write(cpu_tlbstate.loaded_mm, next); write_cr3(__pa(next->pgd)); - /* - * This gets called via leave_mm() in the idle path where RCU - * functions differently. Tracing normally uses RCU, so we - * have to call the tracepoint specially here. - */ - trace_tlb_flush_rcuidle(TLB_FLUSH_ON_TASK_SWITCH, - TLB_FLUSH_ALL); + trace_tlb_flush(TLB_FLUSH_ON_TASK_SWITCH, TLB_FLUSH_ALL); } load_mm_cr4(next); diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 5c8aa9cf62d7..fe3d2a40f311 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -708,8 +708,6 @@ static DEFINE_RAW_SPINLOCK(c3_lock); static void acpi_idle_enter_bm(struct acpi_processor *pr, struct acpi_processor_cx *cx, bool timer_bc) { - acpi_unlazy_tlb(smp_processor_id()); - /* * Must be done before busmaster disable as we might need to * access HPET ! diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 216d7ec88c0c..596b57311de6 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -917,11 +917,11 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev, 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(); -- 2.9.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org