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Subject[PATCH 1/6] x86, mm: Trace when an IPI is about to be sent
Date
It is easy to trace when an IPI is received to flush a TLB but harder to
detect what event sent it. This patch makes it easy to identify the source
of IPIs being transmitted for TLB flushes on x86.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
---
arch/x86/mm/tlb.c | 1 +
include/linux/mm_types.h | 1 +
include/trace/events/tlb.h | 3 ++-
3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 3250f2371aea..2da824c1c140 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -140,6 +140,7 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
info.flush_end = end;

count_vm_tlb_event(NR_TLB_REMOTE_FLUSH);
+ trace_tlb_flush(TLB_REMOTE_SEND_IPI, end - start);
if (is_uv_system()) {
unsigned int cpu;

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 199a03aab8dc..856038aa166e 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -532,6 +532,7 @@ enum tlb_flush_reason {
TLB_REMOTE_SHOOTDOWN,
TLB_LOCAL_SHOOTDOWN,
TLB_LOCAL_MM_SHOOTDOWN,
+ TLB_REMOTE_SEND_IPI,
NR_TLB_FLUSH_REASONS,
};

diff --git a/include/trace/events/tlb.h b/include/trace/events/tlb.h
index 0e7635765153..0fc101472988 100644
--- a/include/trace/events/tlb.h
+++ b/include/trace/events/tlb.h
@@ -11,7 +11,8 @@
{ TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" }, \
{ TLB_REMOTE_SHOOTDOWN, "remote shootdown" }, \
{ TLB_LOCAL_SHOOTDOWN, "local shootdown" }, \
- { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }
+ { TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" }, \
+ { TLB_REMOTE_SEND_IPI, "remote ipi send" }

TRACE_EVENT_CONDITION(tlb_flush,

--
2.1.2


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