[v3,3/3] RISC-V: Update tlb flush counters

Commit Message

Atish Patra April 29, 2019, 9:27 p.m. UTC

The TLB flush counters under vmstat seems to be very helpful while
debugging TLB flush performance in RISC-V.

Update the counters in every TLB flush methods respectively.

Signed-off-by: Atish Patra <[e-mail]>
---
 arch/riscv/include/asm/tlbflush.h |  5 +++++
 arch/riscv/mm/tlbflush.c          | 12 ++++++++++++
 2 files changed, 17 insertions(+)

Comments

Paul Walmsley June 28, 2019, 5:47 a.m. UTC | #1

On Mon, 29 Apr 2019, Atish Patra wrote:

> The TLB flush counters under vmstat seems to be very helpful while
> debugging TLB flush performance in RISC-V.
> 
> Update the counters in every TLB flush methods respectively.
> 
> Signed-off-by: Atish Patra <[e-mail]>

This one doesn't apply any longer.  Care to update and repost?


- Paul

Atish Patra June 28, 2019, 4:37 p.m. UTC | #2

On 6/27/19 10:47 PM, Paul Walmsley wrote:
> On Mon, 29 Apr 2019, Atish Patra wrote:
> 
>> The TLB flush counters under vmstat seems to be very helpful while
>> debugging TLB flush performance in RISC-V.
>>
>> Update the counters in every TLB flush methods respectively.
>>
>> Signed-off-by: Atish Patra <[e-mail]>
> 
> This one doesn't apply any longer.  Care to update and repost?
> 
> 
> - Paul
> 

Yeah. The baseline patch (Gary's patch) was not accepted. I will rebase 
it on top of master and resend.

Patch

diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index 29a780ca232a..19779a083f52 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -9,6 +9,7 @@ 
 #define _ASM_RISCV_TLBFLUSH_H
 
 #include <linux/mm_types.h>
+#include <linux/vmstat.h>
 
 /*
  * Flush entire local TLB.  'sfence.vma' implicitly fences with the instruction
@@ -16,11 +17,13 @@ 
  */
 static inline void local_flush_tlb_all(void)
 {
+	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
 	__asm__ __volatile__ ("sfence.vma" : : : "memory");
 }
 
 static inline void local_flush_tlb_mm(struct mm_struct *mm)
 {
+	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
 	/* Flush ASID 0 so that global mappings are not affected */
 	__asm__ __volatile__ ("sfence.vma x0, %0" : : "r" (0) : "memory");
 }
@@ -28,6 +31,7 @@  static inline void local_flush_tlb_mm(struct mm_struct *mm)
 static inline void local_flush_tlb_page(struct vm_area_struct *vma,
 	unsigned long addr)
 {
+	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
 	__asm__ __volatile__ ("sfence.vma %0, %1"
 			      : : "r" (addr), "r" (0)
 			      : "memory");
@@ -35,6 +39,7 @@  static inline void local_flush_tlb_page(struct vm_area_struct *vma,
 
 static inline void local_flush_tlb_kernel_page(unsigned long addr)
 {
+	count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ONE);
 	__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory");
 }
 
diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index ceee76f14a0a..8072d7da32bb 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -4,6 +4,8 @@ 
  */
 
 #include <linux/mm.h>
+#include <linux/vmstat.h>
+#include <linux/cpumask.h>
 #include <asm/sbi.h>
 
 #define SFENCE_VMA_FLUSH_ALL ((unsigned long) -1)
@@ -110,6 +112,7 @@  static void ipi_remote_sfence_vma(void *info)
 	unsigned long size = data->size;
 	unsigned long i;
 
+	count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
 	if (size == SFENCE_VMA_FLUSH_ALL) {
 		local_flush_tlb_all();
 	}
@@ -129,6 +132,8 @@  static void ipi_remote_sfence_vma_asid(void *info)
 	unsigned long size = data->size;
 	unsigned long i;
 
+	count_vm_tlb_event(NR_TLB_REMOTE_FLUSH_RECEIVED);
+	/* Flush entire MM context */
 	if (size == SFENCE_VMA_FLUSH_ALL) {
 		__asm__ __volatile__ ("sfence.vma x0, %0"
 				      : : "r" (asid)
@@ -158,6 +163,13 @@  static void remote_sfence_vma(unsigned long start, unsigned long size)
 static void remote_sfence_vma_asid(cpumask_t *mask, unsigned long start,
 				   unsigned long size, unsigned long asid)
 {
+	int cpuid = smp_processor_id();
+
+	if (cpumask_equal(mask, cpumask_of(cpuid)))
+		count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL);
+	else
+		count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
+
 	if (tlbi_ipi) {
 		struct tlbi info = {
 			.start = start,