perf/x86/intel/pt: Remove software double buffering PMU capability [Linux 5.1]

perf/x86/intel/pt: Remove software double buffering PMU capability [Linux 5.1]

This Linux kernel change "perf/x86/intel/pt: Remove software double buffering PMU capability" is included in the Linux 5.1 release. This change is authored by Alexander Shishkin <alexander.shishkin [at] linux.intel.com> on Fri May 3 11:55:36 2019 +0300. The commit for this change in Linux stable tree is 72e830f (patch).

perf/x86/intel/pt: Remove software double buffering PMU capability

Now that all AUX allocations are high-order by default, the software
double buffering PMU capability doesn't make sense any more, get rid
of it. In case some PMUs choose to opt out, we can re-introduce it.

Signed-off-by: Alexander Shishkin <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[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]>

There are 4 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 arch/x86/events/intel/pt.c | 3 +--
 include/linux/perf_event.h | 1 -
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index fb3a2f1..339d762 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -1525,8 +1525,7 @@ static __init int pt_init(void)
    }

    if (!intel_pt_validate_hw_cap(PT_CAP_topa_multiple_entries))
-       pt_pmu.pmu.capabilities =
-           PERF_PMU_CAP_AUX_NO_SG | PERF_PMU_CAP_AUX_SW_DOUBLEBUF;
+       pt_pmu.pmu.capabilities = PERF_PMU_CAP_AUX_NO_SG;

    pt_pmu.pmu.capabilities |= PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE;
    pt_pmu.pmu.attr_groups       = pt_attr_groups;
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index e47ef76..1f678f0 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -240,7 +240,6 @@ struct hw_perf_event {
 #define PERF_PMU_CAP_NO_INTERRUPT      0x01
 #define PERF_PMU_CAP_NO_NMI            0x02
 #define PERF_PMU_CAP_AUX_NO_SG         0x04
-#define PERF_PMU_CAP_AUX_SW_DOUBLEBUF      0x08
 #define PERF_PMU_CAP_EXCLUSIVE         0x10
 #define PERF_PMU_CAP_ITRACE            0x20
 #define PERF_PMU_CAP_HETEROGENEOUS_CPUS        0x40

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