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>
diff --git a/mm/filemap.c b/mm/filemap.c
index e1979fd..2581826 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -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 @@
{
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 @@
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 */