[PATCH v2 08/10] mm: frontswap: add tracing support

[Sasha Levin <levinsasha928@xxxxxxxxx>]

Add tracepoints to frontswap API.

Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
---
 include/trace/events/frontswap.h |  167 ++++++++++++++++++++++++++++++++++++++
 mm/frontswap.c                   |   14 +++
 2 files changed, 181 insertions(+), 0 deletions(-)
 create mode 100644 include/trace/events/frontswap.h

diff --git a/include/trace/events/frontswap.h b/include/trace/events/frontswap.h
new file mode 100644
index 0000000..2e5efab
--- /dev/null
+++ b/include/trace/events/frontswap.h
@@ -0,0 +1,167 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM frontswap
+
+#if !defined(_TRACE_FRONTSWAP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_FRONTSWAP_H
+
+#include <linux/tracepoint.h>
+
+struct frontswap_ops;
+
+TRACE_EVENT(frontswap_init,
+	TP_PROTO(unsigned int type, void *sis, void *frontswap_map),
+	TP_ARGS(type, sis, frontswap_map),
+
+	TP_STRUCT__entry(
+		__field(	unsigned int,	type		)
+		__field(	void *,		sis		)
+		__field(	void *,		frontswap_map	)
+	),
+
+	TP_fast_assign(
+		__entry->type		= type;
+		__entry->sis		= sis;
+		__entry->frontswap_map	= frontswap_map;
+	),
+
+	TP_printk("type: %u sis: %p frontswap_map: %p",
+		  __entry->type, __entry->sis, __entry->frontswap_map)
+);
+
+TRACE_EVENT(frontswap_register_ops,
+	TP_PROTO(struct frontswap_ops *old, struct frontswap_ops *new),
+	TP_ARGS(old, new),
+
+	TP_STRUCT__entry(
+		__field(struct frontswap_ops *,		old		)
+		__field(struct frontswap_ops *,		new		)
+	),
+
+	TP_fast_assign(
+		__entry->old		= old;
+		__entry->new		= new;
+	),
+
+	TP_printk("old: {init=%p store=%p load=%p invalidate_page=%p invalidate_area=%p}"
+		" new: {init=%p store=%p load=%p invalidate_page=%p invalidate_area=%p}",
+		__entry->old->init,__entry->old->store,__entry->old->load,
+		__entry->old->invalidate_page,__entry->old->invalidate_area,__entry->new->init,
+		__entry->new->store,__entry->new->load,__entry->new->invalidate_page,
+		__entry->new->invalidate_area)
+);
+
+TRACE_EVENT(frontswap_store,
+	TP_PROTO(void *page, int dup, int ret),
+	TP_ARGS(page, dup, ret),
+
+	TP_STRUCT__entry(
+		__field(	int,		dup		)
+		__field(	int,		ret		)
+		__field(	void *,		page		)
+	),
+
+	TP_fast_assign(
+		__entry->dup		= dup;
+		__entry->ret		= ret;
+		__entry->page		= page;
+	),
+
+	TP_printk("page: %p dup: %d ret: %d",
+		  __entry->page, __entry->dup, __entry->ret)
+);
+
+TRACE_EVENT(frontswap_load,
+	TP_PROTO(void *page, int ret),
+	TP_ARGS(page, ret),
+
+	TP_STRUCT__entry(
+		__field(	int,		ret		)
+		__field(	void *,		page		)
+	),
+
+	TP_fast_assign(
+		__entry->ret		= ret;
+		__entry->page		= page;
+	),
+
+	TP_printk("page: %p ret: %d",
+		  __entry->page, __entry->ret)
+);
+
+TRACE_EVENT(frontswap_invalidate_page,
+	TP_PROTO(int type, unsigned long offset, void *sis, int test),
+	TP_ARGS(type, offset, sis, test),
+
+	TP_STRUCT__entry(
+		__field(	int,		type		)
+		__field(	unsigned long,	offset		)
+		__field(	void *,		sis		)
+		__field(	int,		test		)
+	),
+
+	TP_fast_assign(
+		__entry->type		= type;
+		__entry->offset		= offset;
+		__entry->sis		= sis;
+		__entry->test		= test;
+	),
+
+	TP_printk("type: %d offset: %lu sys: %p frontswap_test: %d",
+		  __entry->type, __entry->offset, __entry->sis, __entry->test)
+);
+
+TRACE_EVENT(frontswap_invalidate_area,
+	TP_PROTO(int type, void *sis, void *map),
+	TP_ARGS(type, sis, map),
+
+	TP_STRUCT__entry(
+		__field(	int,		type		)
+		__field(	void *,		map		)
+		__field(	void *,		sis		)
+	),
+
+	TP_fast_assign(
+		__entry->type		= type;
+		__entry->sis		= sis;
+		__entry->map		= map;
+	),
+
+	TP_printk("type: %d sys: %p map: %p",
+		  __entry->type, __entry->sis, __entry->map)
+);
+
+TRACE_EVENT(frontswap_curr_pages,
+	TP_PROTO(unsigned long totalpages),
+	TP_ARGS(totalpages),
+
+	TP_STRUCT__entry(
+		__field(unsigned long,		totalpages	)
+	),
+
+	TP_fast_assign(
+		__entry->totalpages	= totalpages;
+	),
+
+	TP_printk("total pages: %lu",
+		  __entry->totalpages)
+);
+
+TRACE_EVENT(frontswap_shrink,
+	TP_PROTO(unsigned long target_pages),
+	TP_ARGS(target_pages),
+
+	TP_STRUCT__entry(
+		__field(unsigned long,		target_pages	)
+	),
+
+	TP_fast_assign(
+		__entry->target_pages	= target_pages;
+	),
+
+	TP_printk("target pages: %lu",
+		  __entry->target_pages)
+);
+
+#endif /* _TRACE_FRONTSWAP_H */
+
+#include <trace/define_trace.h>
diff --git a/mm/frontswap.c b/mm/frontswap.c
index 0319fc5..0250c20 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -11,6 +11,7 @@
  * This work is licensed under the terms of the GNU GPL, version 2.
  */
 
+#define CREATE_TRACE_POINTS
 #include <linux/mm.h>
 #include <linux/mman.h>
 #include <linux/swap.h>
@@ -23,6 +24,7 @@
 #include <linux/debugfs.h>
 #include <linux/frontswap.h>
 #include <linux/swapfile.h>
+#include <trace/events/frontswap.h>
 
 /*
  * frontswap_ops is set by frontswap_register_ops to contain the pointers
@@ -85,6 +87,7 @@ struct frontswap_ops frontswap_register_ops(struct frontswap_ops *ops)
 {
 	struct frontswap_ops old = frontswap_ops;
 
+	trace_frontswap_register_ops(&old, ops);
 	frontswap_ops = *ops;
 	frontswap_enabled = true;
 	return old;
@@ -108,6 +111,9 @@ void __frontswap_init(unsigned type)
 	struct swap_info_struct *sis = swap_info[type];
 
 	BUG_ON(sis == NULL);
+
+	trace_frontswap_init(type, sis, sis->frontswap_map);
+
 	if (sis->frontswap_map == NULL)
 		return;
 	frontswap_ops.init(type);
@@ -134,6 +140,7 @@ int __frontswap_store(struct page *page)
 	if (frontswap_test(sis, offset))
 		dup = 1;
 	ret = frontswap_ops.store(type, offset, page);
+	trace_frontswap_store(page, dup, ret);
 	if (ret == 0) {
 		frontswap_set(sis, offset);
 		inc_frontswap_succ_stores();
@@ -174,6 +181,7 @@ int __frontswap_load(struct page *page)
 	BUG_ON(sis == NULL);
 	if (frontswap_test(sis, offset))
 		ret = frontswap_ops.load(type, offset, page);
+	trace_frontswap_load(page, ret);
 	if (ret == 0)
 		inc_frontswap_loads();
 	return ret;
@@ -189,6 +197,7 @@ void __frontswap_invalidate_page(unsigned type, pgoff_t offset)
 	struct swap_info_struct *sis = swap_info[type];
 
 	BUG_ON(sis == NULL);
+	trace_frontswap_invalidate_page(type, offset, sis, frontswap_test(sis, offset));
 	if (frontswap_test(sis, offset)) {
 		frontswap_ops.invalidate_page(type, offset);
 		atomic_dec(&sis->frontswap_pages);
@@ -207,6 +216,7 @@ void __frontswap_invalidate_area(unsigned type)
 	struct swap_info_struct *sis = swap_info[type];
 
 	BUG_ON(sis == NULL);
+	trace_frontswap_invalidate_area(type, sis, sis->frontswap_map);
 	if (sis->frontswap_map == NULL)
 		return;
 	frontswap_ops.invalidate_area(type);
@@ -295,6 +305,8 @@ void frontswap_shrink(unsigned long target_pages)
 	unsigned long pages_to_unuse = 0;
 	int type, ret;
 
+	trace_frontswap_shrink(target_pages);
+
 	/*
 	 * we don't want to hold swap_lock while doing a very
 	 * lengthy try_to_unuse, but swap_list may change
@@ -322,6 +334,8 @@ unsigned long frontswap_curr_pages(void)
 	totalpages = __frontswap_curr_pages();
 	spin_unlock(&swap_lock);
 
+	trace_frontswap_curr_pages(totalpages);
+
 	return totalpages;
 }
 EXPORT_SYMBOL(frontswap_curr_pages);
-- 
1.7.8.6

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