mm: compaction: add trace events for memory compaction activity
In preparation for a patches promoting the use of memory compaction over
lumpy reclaim, this patch adds trace points for memory compaction
activity. Using them, we can monitor the scanning activity of the
migration and free page scanners as well as the number and success rates
of pages passed to page migration.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/compaction.c b/mm/compaction.c
index 1a8894e..20011a8 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -16,6 +16,9 @@
#include <linux/sysfs.h>
#include "internal.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/compaction.h>
+
/*
* compact_control is used to track pages being migrated and the free pages
* they are being migrated to during memory compaction. The free_pfn starts
@@ -60,7 +63,7 @@
struct list_head *freelist)
{
unsigned long zone_end_pfn, end_pfn;
- int total_isolated = 0;
+ int nr_scanned = 0, total_isolated = 0;
struct page *cursor;
/* Get the last PFN we should scan for free pages at */
@@ -81,6 +84,7 @@
if (!pfn_valid_within(blockpfn))
continue;
+ nr_scanned++;
if (!PageBuddy(page))
continue;
@@ -100,6 +104,7 @@
}
}
+ trace_mm_compaction_isolate_freepages(nr_scanned, total_isolated);
return total_isolated;
}
@@ -234,6 +239,7 @@
struct compact_control *cc)
{
unsigned long low_pfn, end_pfn;
+ unsigned long nr_scanned = 0, nr_isolated = 0;
struct list_head *migratelist = &cc->migratepages;
/* Do not scan outside zone boundaries */
@@ -266,6 +272,7 @@
struct page *page;
if (!pfn_valid_within(low_pfn))
continue;
+ nr_scanned++;
/* Get the page and skip if free */
page = pfn_to_page(low_pfn);
@@ -280,6 +287,7 @@
del_page_from_lru_list(zone, page, page_lru(page));
list_add(&page->lru, migratelist);
cc->nr_migratepages++;
+ nr_isolated++;
/* Avoid isolating too much */
if (cc->nr_migratepages == COMPACT_CLUSTER_MAX)
@@ -291,6 +299,8 @@
spin_unlock_irq(&zone->lru_lock);
cc->migrate_pfn = low_pfn;
+ trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
+
return cc->nr_migratepages;
}
@@ -401,6 +411,8 @@
count_vm_events(COMPACTPAGES, nr_migrate - nr_remaining);
if (nr_remaining)
count_vm_events(COMPACTPAGEFAILED, nr_remaining);
+ trace_mm_compaction_migratepages(nr_migrate - nr_remaining,
+ nr_remaining);
/* Release LRU pages not migrated */
if (!list_empty(&cc->migratepages)) {