[RFC PATCH -tip 1/1] tracepoints: add tracepoints for pagecache

Keiichi KII
2009-12-12T00:59:52Z

This patch adds several tracepoints to track pagecach behavior.
These trecepoints would help us monitor pagecache usage with high resolution.

Signed-off-by: Keiichi Kii <k-keiichi@bx.jp.nec.com>
Cc: Atsushi Tsuji <a-tsuji@bk.jp.nec.com>
---
include/trace/events/filemap.h | 83 +++++++++++++++++++++++++++++++++++++++++
mm/filemap.c | 5 ++
mm/truncate.c | 2
mm/vmscan.c | 3 +
4 files changed, 93 insertions(+)

Index: linux-2.6-tip/include/trace/events/filemap.h
===================================================================
--- /dev/null
+++ linux-2.6-tip/include/trace/events/filemap.h
@@ -0,0 +1,83 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM filemap
+
+#if !defined(_TRACE_FILEMAP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_FILEMAP_H
+
+#include <linux/fs.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(find_get_page,
+
+ TP_PROTO(struct address_space *mapping, pgoff_t offset,
+ struct page * page),
+
+ TP_ARGS(mapping, offset, page),
+
+ TP_STRUCT__entry(
+ __field(dev_t, s_dev)
+ __field(ino_t, i_ino)
+ __field(pgoff_t, offset)
+ __field(struct page *, page)
+ ),
+
+ TP_fast_assign(
+ __entry->s_dev = mapping->host ? mapping->host->i_sb->s_dev : 0;
+ __entry->i_ino = mapping->host ? mapping->host->i_ino : 0;
+ __entry->offset = offset;
+ __entry->page = page;
+ ),
+
+ TP_printk("s_dev=%u:%u i_ino=%lu offset=%lu %s", MAJOR(__entry->s_dev),
+ MINOR(__entry->s_dev), __entry->i_ino, __entry->offset,
+ __entry->page == NULL ? "page_not_found" : "page_found")
+);
+
+TRACE_EVENT(add_to_page_cache,
+
+ TP_PROTO(struct address_space *mapping, pgoff_t offset),
+
+ TP_ARGS(mapping, offset),
+
+ TP_STRUCT__entry(
+ __field(dev_t, s_dev)
+ __field(ino_t, i_ino)
+ __field(pgoff_t, offset)
+ ),
+
+ TP_fast_assign(
+ __entry->s_dev = mapping->host->i_sb->s_dev;
+ __entry->i_ino = mapping->host->i_ino;
+ __entry->offset = offset;
+ ),
+
+ TP_printk("s_dev=%u:%u i_ino=%lu offset=%lu", MAJOR(__entry->s_dev),
+ MINOR(__entry->s_dev), __entry->i_ino, __entry->offset)
+);
+
+TRACE_EVENT(remove_from_page_cache,
+
+ TP_PROTO(struct address_space *mapping, pgoff_t offset),
+
+ TP_ARGS(mapping, offset),
+
+ TP_STRUCT__entry(
+ __field(dev_t, s_dev)
+ __field(ino_t, i_ino)
+ __field(pgoff_t, offset)
+ ),
+
+ TP_fast_assign(
+ __entry->s_dev = mapping->host->i_sb->s_dev;
+ __entry->i_ino = mapping->host->i_ino;
+ __entry->offset = offset;
+ ),
+
+ TP_printk("s_dev=%u:%u i_ino=%lu offset=%lu", MAJOR(__entry->s_dev),
+ MINOR(__entry->s_dev), __entry->i_ino, __entry->offset)
+);
+
+#endif /* _TRACE_FILEMAP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
Index: linux-2.6-tip/mm/filemap.c
===================================================================
--- linux-2.6-tip.orig/mm/filemap.c
+++ linux-2.6-tip/mm/filemap.c
@@ -34,6 +34,8 @@
#include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
#include <linux/memcontrol.h>
#include <linux/mm_inline.h> /* for page_is_file_cache() */
+#define CREATE_TRACE_POINTS
+#include <trace/events/filemap.h>
#include "internal.h"

/*
@@ -149,6 +151,7 @@ void remove_from_page_cache(struct page
spin_lock_irq(&mapping->tree_lock);
__remove_from_page_cache(page);
spin_unlock_irq(&mapping->tree_lock);
+ trace_remove_from_page_cache(mapping, page->index);
mem_cgroup_uncharge_cache_page(page);
}

@@ -440,6 +443,7 @@ int add_to_page_cache_locked(struct page
if (PageSwapBacked(page))
__inc_zone_page_state(page, NR_SHMEM);
spin_unlock_irq(&mapping->tree_lock);
+ trace_add_to_page_cache(mapping, offset);
} else {
page->mapping = NULL;
spin_unlock_irq(&mapping->tree_lock);
@@ -663,6 +667,7 @@ repeat:
}
rcu_read_unlock();

+ trace_find_get_page(mapping, offset, page);
return page;
}
EXPORT_SYMBOL(find_get_page);
Index: linux-2.6-tip/mm/truncate.c
===================================================================
--- linux-2.6-tip.orig/mm/truncate.c
+++ linux-2.6-tip/mm/truncate.c
@@ -20,6 +20,7 @@
do_invalidatepage */
#include "internal.h"

+#include <trace/events/filemap.h>

/**
* do_invalidatepage - invalidate part or all of a page
@@ -384,6 +385,7 @@ invalidate_complete_page2(struct address
BUG_ON(page_has_private(page));
__remove_from_page_cache(page);
spin_unlock_irq(&mapping->tree_lock);
+ trace_remove_from_page_cache(mapping, page->index);
mem_cgroup_uncharge_cache_page(page);
page_cache_release(page); /* pagecache ref */
return 1;
Index: linux-2.6-tip/mm/vmscan.c
===================================================================
--- linux-2.6-tip.orig/mm/vmscan.c
+++ linux-2.6-tip/mm/vmscan.c
@@ -48,6 +48,8 @@

#include "internal.h"

+#include <trace/events/filemap.h>
+
struct scan_control {
/* Incremented by the number of inactive pages that were scanned */
unsigned long nr_scanned;
@@ -478,6 +480,7 @@ static int __remove_mapping(struct addre
} else {
__remove_from_page_cache(page);
spin_unlock_irq(&mapping->tree_lock);
+ trace_remove_from_page_cache(mapping, page->index);
mem_cgroup_uncharge_cache_page(page);
}