mm: cma: add trace events for CMA alloc perf testing

Add cma and migrate trace events to enable CMA allocation performance to
be measured via ftrace.

[georgi.djakov@linaro.org: add the CMA instance name to the cma_alloc_start trace event]
  Link: https://lkml.kernel.org/r/20210326155414.25006-1-georgi.djakov@linaro.org

Link: https://lkml.kernel.org/r/20210324160740.15901-1-georgi.djakov@linaro.org
Signed-off-by: Liam Mark <lmark@codeaurora.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/trace/events/cma.h

@@ -8,7 +8,7 @@
 #include <linux/types.h>
 #include <linux/tracepoint.h>
 
-TRACE_EVENT(cma_alloc,
+DECLARE_EVENT_CLASS(cma_alloc_class,
 
 	TP_PROTO(unsigned long pfn, const struct page *page,
 		 unsigned int count, unsigned int align),
@@ -61,6 +61,46 @@ TRACE_EVENT(cma_release,
 		  __entry->count)
 );
 
+TRACE_EVENT(cma_alloc_start,
+
+	TP_PROTO(const char *name, unsigned int count, unsigned int align),
+
+	TP_ARGS(name, count, align),
+
+	TP_STRUCT__entry(
+		__string(name, name)
+		__field(unsigned int, count)
+		__field(unsigned int, align)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, name);
+		__entry->count = count;
+		__entry->align = align;
+	),
+
+	TP_printk("name=%s count=%u align=%u",
+		  __get_str(name),
+		  __entry->count,
+		  __entry->align)
+);
+
+DEFINE_EVENT(cma_alloc_class, cma_alloc,
+
+	TP_PROTO(unsigned long pfn, const struct page *page,
+		 unsigned int count, unsigned int align),
+
+	TP_ARGS(pfn, page, count, align)
+);
+
+DEFINE_EVENT(cma_alloc_class, cma_alloc_busy_retry,
+
+	TP_PROTO(unsigned long pfn, const struct page *page,
+		 unsigned int count, unsigned int align),
+
+	TP_ARGS(pfn, page, count, align)
+);
+
 #endif /* _TRACE_CMA_H */
 
 /* This part must be outside protection */

include/trace/events/migrate.h

@@ -81,6 +81,28 @@ TRACE_EVENT(mm_migrate_pages,
 		__print_symbolic(__entry->mode, MIGRATE_MODE),
 		__print_symbolic(__entry->reason, MIGRATE_REASON))
 );
+
+TRACE_EVENT(mm_migrate_pages_start,
+
+	TP_PROTO(enum migrate_mode mode, int reason),
+
+	TP_ARGS(mode, reason),
+
+	TP_STRUCT__entry(
+		__field(enum migrate_mode, mode)
+		__field(int, reason)
+	),
+
+	TP_fast_assign(
+		__entry->mode	= mode;
+		__entry->reason	= reason;
+	),
+
+	TP_printk("mode=%s reason=%s",
+		  __print_symbolic(__entry->mode, MIGRATE_MODE),
+		  __print_symbolic(__entry->reason, MIGRATE_REASON))
+);
+
 #endif /* _TRACE_MIGRATE_H */
 
 /* This part must be outside protection */

mm/cma.c

@@ -443,6 +443,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
 	if (!count)
 		goto out;
 
+	trace_cma_alloc_start(cma->name, count, align);
+
 	mask = cma_bitmap_aligned_mask(cma, align);
 	offset = cma_bitmap_aligned_offset(cma, align);
 	bitmap_maxno = cma_bitmap_maxno(cma);
@@ -483,6 +485,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
 
 		pr_debug("%s(): memory range at %p is busy, retrying\n",
 			 __func__, pfn_to_page(pfn));
+
+		trace_cma_alloc_busy_retry(pfn, pfn_to_page(pfn), count, align);
 		/* try again with a bit different memory target */
 		start = bitmap_no + mask + 1;
 	}

mm/migrate.c

@@ -1418,6 +1418,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
 	int rc, nr_subpages;
 	LIST_HEAD(ret_pages);
 
+	trace_mm_migrate_pages_start(mode, reason);
+
 	if (!swapwrite)
 		current->flags |= PF_SWAPWRITE;