s390/cpum_sf: Dynamically extend the sampling buffer if overflows occur
Improve the sampling buffer allocation and add a function to reallocate and
increase the sampling buffer structure. The number of allocated buffer elements
(sample-data-blocks) are accounted. You can control the minimum and maximum
number these sample-data-blocks through the cpum_sfb_size kernel parameter.
The number hardware sample overflows (if any) are also accounted and stored
per perf event. During the PMU disable/enable calls, the accumulated overflow
counter is analyzed and, if necessary, the sampling buffer is dynamically
increased.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/perf_event.h b/arch/s390/include/asm/perf_event.h
index 23d2dfa..99d7f4e 100644
--- a/arch/s390/include/asm/perf_event.h
+++ b/arch/s390/include/asm/perf_event.h
@@ -49,6 +49,10 @@
#define PERF_CPUM_SF_MAX_CTR 1
#define PERF_EVENT_CPUM_SF 0xB0000UL /* Raw event ID */
+#define REG_NONE 0
+#define REG_OVERFLOW 1
+#define OVERFLOW_REG(hwc) ((hwc)->extra_reg.config)
+#define SFB_ALLOC_REG(hwc) ((hwc)->extra_reg.alloc)
#define TEAR_REG(hwc) ((hwc)->last_tag)
#define SAMPL_RATE(hwc) ((hwc)->event_base)