Commit-ID:  bcfbe5c41d630ce6b74da45134cea484248b515a
Gitweb:     https://git.kernel.org/tip/bcfbe5c41d630ce6b74da45134cea484248b515a
Author:     Kan Liang <[email protected]>
AuthorDate: Mon, 12 Feb 2018 14:20:32 -0800
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 9 Mar 2018 08:22:20 +0100

perf/x86: Introduce a ->read() callback in 'struct x86_pmu'

Auto-reload needs to be specially handled when reading event counts.

Signed-off-by: Kan Liang <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vince Weaver <[email protected]>
Cc: [email protected]
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 arch/x86/events/core.c       | 2 ++
 arch/x86/events/perf_event.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 5a3ccd1715e2..00a6251981d2 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1881,6 +1881,8 @@ early_initcall(init_hw_perf_events);
 
 static inline void x86_pmu_read(struct perf_event *event)
 {
+       if (x86_pmu.read)
+               return x86_pmu.read(event);
        x86_perf_event_update(event);
 }
 
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 6495ffd57e3e..d445f0026989 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -520,6 +520,7 @@ struct x86_pmu {
        void            (*disable)(struct perf_event *);
        void            (*add)(struct perf_event *);
        void            (*del)(struct perf_event *);
+       void            (*read)(struct perf_event *event);
        int             (*hw_config)(struct perf_event *event);
        int             (*schedule_events)(struct cpu_hw_events *cpuc, int n, 
int *assign);
        unsigned        eventsel;

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