[PATCH 4/4] mm: cma: add trace events to debug physically-contiguous memory allocations

[Stefan Strogin]

Add trace events for cma_alloc() and cma_release().

Signed-off-by: Stefan Strogin <s.strogin@xxxxxxxxxxxxxxxxxxx>
---
 include/trace/events/cma.h | 57 ++++++++++++++++++++++++++++++++++++++++++++++
 mm/cma.c                   |  7 +++++-
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 include/trace/events/cma.h

diff --git a/include/trace/events/cma.h b/include/trace/events/cma.h
new file mode 100644
index 0000000..3fe7a56
--- /dev/null
+++ b/include/trace/events/cma.h
@@ -0,0 +1,57 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM cma
+
+#if !defined(_TRACE_CMA_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_CMA_H
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(cma_alloc,
+
+	TP_PROTO(struct cma *cma, unsigned long pfn, int count),
+
+	TP_ARGS(cma, pfn, count),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, pfn)
+		__field(unsigned long, count)
+	),
+
+	TP_fast_assign(
+		__entry->pfn = pfn;
+		__entry->count = count;
+	),
+
+	TP_printk("pfn=%lu page=%p count=%lu\n",
+		  __entry->pfn,
+		  pfn_to_page(__entry->pfn),
+		  __entry->count)
+);
+
+TRACE_EVENT(cma_release,
+
+	TP_PROTO(struct cma *cma, unsigned long pfn, int count),
+
+	TP_ARGS(cma, pfn, count),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, pfn)
+		__field(unsigned long, count)
+	),
+
+	TP_fast_assign(
+		__entry->pfn = pfn;
+		__entry->count = count;
+	),
+
+	TP_printk("pfn=%lu page=%p count=%lu\n",
+		  __entry->pfn,
+		  pfn_to_page(__entry->pfn),
+		  __entry->count)
+);
+
+#endif /* _TRACE_CMA_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/mm/cma.c b/mm/cma.c
index c68d383..a7bd7f0 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -23,6 +23,7 @@
 #  define DEBUG
 #endif
 #endif
+#define CREATE_TRACE_POINTS
 
 #include <linux/memblock.h>
 #include <linux/err.h>
@@ -37,6 +38,7 @@
 #include <linux/list.h>
 #include <linux/proc_fs.h>
 #include <linux/time.h>
+#include <trace/events/cma.h>
 
 #include "cma.h"
 
@@ -443,8 +445,10 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
 		start = bitmap_no + mask + 1;
 	}
 
-	if (page)
+	if (page) {
 		cma_buffer_list_add(cma, pfn, count);
+		trace_cma_alloc(cma, pfn, count);
+	}
 
 	pr_debug("%s(): returned %p\n", __func__, page);
 	return page;
@@ -478,6 +482,7 @@ bool cma_release(struct cma *cma, struct page *pages, int count)
 
 	free_contig_range(pfn, count);
 	cma_clear_bitmap(cma, pfn, count);
+	trace_cma_release(cma, pfn, count);
 	cma_buffer_list_del(cma, pfn, count);
 
 	return true;
-- 
2.1.0

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