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Commit fe0bfaaf authored by Robert Jarzmik's avatar Robert Jarzmik Committed by Linus Torvalds
Browse files

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: default avatarRobert 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e3986295

include/trace/events/filemap.h

0 → 100644
+58 −0
Original line number Diff line number Diff line 
#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>

mm/filemap.c

+5 −0
Original line number Diff line number Diff line
@@ -35,6 +35,9 @@ 
#include <linux/cleancache.h>

#include "internal.h"



#define CREATE_TRACE_POINTS

#include <trace/events/filemap.h>



/*

 * FIXME: remove all knowledge of the buffer layer from the core VM

 */
@@ -113,6 +116,7 @@ void __delete_from_page_cache(struct page *page) 
{

	struct address_space *mapping = page->mapping;



	trace_mm_filemap_delete_from_page_cache(page);

	/*

	 * if we're uptodate, flush out into the cleancache, otherwise

	 * invalidate any existing cleancache entries.  We can't leave
@@ -464,6 +468,7 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping, 
			mapping->nrpages++;

			__inc_zone_page_state(page, NR_FILE_PAGES);

			spin_unlock_irq(&mapping->tree_lock);

			trace_mm_filemap_add_to_page_cache(page);

		} else {

			page->mapping = NULL;

			/* Leave page->index set: truncation relies upon it */