linux-kernel - [PATCH v3 3/3] RISC-V: Update tlb flush counters

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Date:   Mon, 29 Apr 2019 14:27:50 -0700
From:   Atish Patra <atish.patra@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Atish Patra <atish.patra@....com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Anup Patel <anup@...infault.org>,
        Borislav Petkov <bp@...en8.de>,
        Changbin Du <changbin.du@...el.com>,
        Gary Guo <gary@...yguo.net>, "H. Peter Anvin" <hpa@...or.com>,
        Ingo Molnar <mingo@...hat.com>,
        Kees Cook <keescook@...omium.org>, linux-mm@...ck.org,
        linux-riscv@...ts.infradead.org,
        Luc Van Oostenryck <luc.vanoostenryck@...il.com>,
        Palmer Dabbelt <palmer@...ive.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Vlastimil Babka <vbabka@...e.cz>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        Christoph Hellwig <hch@...radead.org>
Subject: [PATCH v3 3/3] RISC-V: Update tlb flush counters

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 <atish.patra@....com>
---
 arch/riscv/include/asm/tlbflush.h |  5 +++++
 arch/riscv/mm/tlbflush.c          | 12 ++++++++++++
 2 files changed, 17 insertions(+)

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,
-- 
2.21.0