From fe0bfaaff84429a35e4447d4ccd646aecf5999fb Mon Sep 17 00:00:00 2001
From: Robert Jarzmik <robert.jarzmik@free.fr>
Date: Mon, 29 Apr 2013 15:06:10 -0700
Subject: mm: trace filemap add and del

Use the events API to trace filemap loading and unloading of file pieces
into the page cache.

This patch aims at tracing the eviction reload cycle of executable and
shared libraries pages in a memory constrained environment.

The typical usage is to spot a specific device and inode (for example
/lib/libc.so) to see the eviction cycles, and find out if frequently
used code is rather spread across many pages (bad) or coallesced (good).

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 include/trace/events/filemap.h | 58 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 include/trace/events/filemap.h

(limited to 'include/trace')

diff --git a/include/trace/events/filemap.h b/include/trace/events/filemap.h
new file mode 100644
index 00000000000..0421f49a20f
--- /dev/null
+++ b/include/trace/events/filemap.h
@@ -0,0 +1,58 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM filemap
+
+#if !defined(_TRACE_FILEMAP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_FILEMAP_H
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+#include <linux/mm.h>
+#include <linux/memcontrol.h>
+#include <linux/device.h>
+#include <linux/kdev_t.h>
+
+DECLARE_EVENT_CLASS(mm_filemap_op_page_cache,
+
+	TP_PROTO(struct page *page),
+
+	TP_ARGS(page),
+
+	TP_STRUCT__entry(
+		__field(struct page *, page)
+		__field(unsigned long, i_ino)
+		__field(unsigned long, index)
+		__field(dev_t, s_dev)
+	),
+
+	TP_fast_assign(
+		__entry->page = page;
+		__entry->i_ino = page->mapping->host->i_ino;
+		__entry->index = page->index;
+		if (page->mapping->host->i_sb)
+			__entry->s_dev = page->mapping->host->i_sb->s_dev;
+		else
+			__entry->s_dev = page->mapping->host->i_rdev;
+	),
+
+	TP_printk("dev %d:%d ino %lx page=%p pfn=%lu ofs=%lu",
+		MAJOR(__entry->s_dev), MINOR(__entry->s_dev),
+		__entry->i_ino,
+		__entry->page,
+		page_to_pfn(__entry->page),
+		__entry->index << PAGE_SHIFT)
+);
+
+DEFINE_EVENT(mm_filemap_op_page_cache, mm_filemap_delete_from_page_cache,
+	TP_PROTO(struct page *page),
+	TP_ARGS(page)
+	);
+
+DEFINE_EVENT(mm_filemap_op_page_cache, mm_filemap_add_to_page_cache,
+	TP_PROTO(struct page *page),
+	TP_ARGS(page)
+	);
+
+#endif /* _TRACE_FILEMAP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
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