[PATCH 2/6] tracing, vmscan: Add trace events for LRU page isolation

Mel Gorman
2010-06-08T09:02:32Z

This patch adds an event for when pages are isolated en-masse from the
LRU lists. This event augments the information available on LRU traffic
and can be used to evaluate lumpy reclaim.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---
include/trace/events/vmscan.h | 46 +++++++++++++++++++++++++++++++++++++++++
mm/vmscan.c | 14 ++++++++++++
2 files changed, 60 insertions(+), 0 deletions(-)

diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index f76521f..a331454 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -109,6 +109,52 @@ TRACE_EVENT(mm_vmscan_direct_reclaim_end,
TP_printk("nr_reclaimed=%lu", __entry->nr_reclaimed)
);

+TRACE_EVENT(mm_vmscan_lru_isolate,
+
+ TP_PROTO(int order,
+ unsigned long nr_requested,
+ unsigned long nr_scanned,
+ unsigned long nr_taken,
+ unsigned long nr_lumpy_taken,
+ unsigned long nr_lumpy_dirty,
+ unsigned long nr_lumpy_failed,
+ int isolate_mode),
+
+ TP_ARGS(order, nr_requested, nr_scanned, nr_taken, nr_lumpy_taken, nr_lumpy_dirty, nr_lumpy_failed, isolate_mode),
+
+ TP_STRUCT__entry(
+ __field(int, order)
+ __field(unsigned long, nr_requested)
+ __field(unsigned long, nr_scanned)
+ __field(unsigned long, nr_taken)
+ __field(unsigned long, nr_lumpy_taken)
+ __field(unsigned long, nr_lumpy_dirty)
+ __field(unsigned long, nr_lumpy_failed)
+ __field(int, isolate_mode)
+ ),
+
+ TP_fast_assign(
+ __entry->order = order;
+ __entry->nr_requested = nr_requested;
+ __entry->nr_scanned = nr_scanned;
+ __entry->nr_taken = nr_taken;
+ __entry->nr_lumpy_taken = nr_lumpy_taken;
+ __entry->nr_lumpy_dirty = nr_lumpy_dirty;
+ __entry->nr_lumpy_failed = nr_lumpy_failed;
+ __entry->isolate_mode = isolate_mode;
+ ),
+
+ TP_printk("isolate_mode=%d order=%d nr_requested=%lu nr_scanned=%lu nr_taken=%lu contig_taken=%lu contig_dirty=%lu contig_failed=%lu",
+ __entry->isolate_mode,
+ __entry->order,
+ __entry->nr_requested,
+ __entry->nr_scanned,
+ __entry->nr_taken,
+ __entry->nr_lumpy_taken,
+ __entry->nr_lumpy_dirty,
+ __entry->nr_lumpy_failed)
+);
+
#endif /* _TRACE_VMSCAN_H */

/* This part must be outside protection */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6bfb579..25bf05a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -917,6 +917,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
unsigned long *scanned, int order, int mode, int file)
{
unsigned long nr_taken = 0;
+ unsigned long nr_lumpy_taken = 0, nr_lumpy_dirty = 0, nr_lumpy_failed = 0;
unsigned long scan;

for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) {
@@ -994,12 +995,25 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
list_move(&cursor_page->lru, dst);
mem_cgroup_del_lru(cursor_page);
nr_taken++;
+ nr_lumpy_taken++;
+ if (PageDirty(cursor_page))
+ nr_lumpy_dirty++;
scan++;
+ } else {
+ if (mode == ISOLATE_BOTH &&
+ page_count(cursor_page))
+ nr_lumpy_failed++;
}
}
}

*scanned = scan;
+
+ trace_mm_vmscan_lru_isolate(order,
+ nr_to_scan, scan,
+ nr_taken,
+ nr_lumpy_taken, nr_lumpy_dirty, nr_lumpy_failed,
+ mode);
return nr_taken;
}

--
1.7.1