mm: cma: add trace events for CMA allocations and freeings

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

The cma_alloc tracepoint is used both for successful and failed allocations,
in case of allocation failure pfn=-1UL is stored and printed.
Signed-off-by: Stefan Strogin <stefan.strogin@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Nazarewicz <mpn@google.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/trace/events/cma.h

+#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(unsigned long pfn, const struct page *page,
+		 unsigned int count, unsigned int align),
+
+	TP_ARGS(pfn, page, count, align),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, pfn)
+		__field(const struct page *, page)
+		__field(unsigned int, count)
+		__field(unsigned int, align)
+	),
+
+	TP_fast_assign(
+		__entry->pfn = pfn;
+		__entry->page = page;
+		__entry->count = count;
+		__entry->align = align;
+	),
+
+	TP_printk("pfn=%lx page=%p count=%u align=%u",
+		  __entry->pfn,
+		  __entry->page,
+		  __entry->count,
+		  __entry->align)
+);
+
+TRACE_EVENT(cma_release,
+
+	TP_PROTO(unsigned long pfn, const struct page *page,
+		 unsigned int count),
+
+	TP_ARGS(pfn, page, count),
+
+	TP_STRUCT__entry(
+		__field(unsigned long, pfn)
+		__field(const struct page *, page)
+		__field(unsigned int, count)
+	),
+
+	TP_fast_assign(
+		__entry->pfn = pfn;
+		__entry->page = page;
+		__entry->count = count;
+	),
+
+	TP_printk("pfn=%lx page=%p count=%u",
+		  __entry->pfn,
+		  __entry->page,
+		  __entry->count)
+);
+
+#endif /* _TRACE_CMA_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

mm/cma.c

@@ -23,6 +23,7 @@
 #  define DEBUG
 #endif
 #endif
+#define CREATE_TRACE_POINTS
 
 #include <linux/memblock.h>
 #include <linux/err.h>
@@ -34,6 +35,7 @@
 #include <linux/cma.h>
 #include <linux/highmem.h>
 #include <linux/io.h>
+#include <trace/events/cma.h>
 
 #include "cma.h"
 
@@ -414,6 +416,8 @@ struct page *cma_alloc(struct cma *cma, unsigned int count, unsigned int align)
 		start = bitmap_no + mask + 1;
 	}
 
+	trace_cma_alloc(page ? pfn : -1UL, page, count, align);
+
 	pr_debug("%s(): returned %p\n", __func__, page);
 	return page;
 }
@@ -446,6 +450,7 @@ bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
 
 	free_contig_range(pfn, count);
 	cma_clear_bitmap(cma, pfn, count);
+	trace_cma_release(pfn, pages, count);
 
 	return true;
 }