[PATCH 1/5] x86/mm: Account for remote kernel TLB flush requests

["Chuyi Zhou" <zhouchuyi@bytedance.com>]

NR_TLB_REMOTE_FLUSH counts requests to invalidate TLB entries on other
CPUs. flush_tlb_all() and native_flush_tlb_multi() account for these
requests, but flush_tlb_kernel_range() bypasses both functions and does
not update the counter. Kernel range flushes are therefore missing from
the sender-side statistics, including ranges promoted to a full flush.

Count each request in kernel_tlb_flush_all() and
kernel_tlb_flush_range(). Account for both IPI and INVLPGB backends, as
flush_tlb_all() already does, and count once per request regardless of
the number of target CPUs or invalidation instructions.

Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
---
 arch/x86/mm/tlb.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 0c4da320831c..da7c408f921c 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -1488,6 +1488,8 @@ static void do_kernel_range_flush(void *info)
 
 static void kernel_tlb_flush_all(struct flush_tlb_info *info)
 {
+	count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
+
 	if (cpu_feature_enabled(X86_FEATURE_INVLPGB))
 		invlpgb_flush_all();
 	else
@@ -1496,6 +1498,8 @@ static void kernel_tlb_flush_all(struct flush_tlb_info *info)
 
 static void kernel_tlb_flush_range(struct flush_tlb_info *info)
 {
+	count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
+
 	if (cpu_feature_enabled(X86_FEATURE_INVLPGB))
 		invlpgb_kernel_range_flush(info);
 	else

base-commit: e81ee06308379a5f2ededf997bcf17551bce5db7
-- 
2.20.1