linux/include/trace/events/compaction.h
Vlastimil Babka f8c9301fa5 mm/compaction: do not count migratepages when unnecessary
During compaction, update_nr_listpages() has been used to count remaining
non-migrated and free pages after a call to migrage_pages().  The
freepages counting has become unneccessary, and it turns out that
migratepages counting is also unnecessary in most cases.

The only situation when it's needed to count cc->migratepages is when
migrate_pages() returns with a negative error code.  Otherwise, the
non-negative return value is the number of pages that were not migrated,
which is exactly the count of remaining pages in the cc->migratepages
list.

Furthermore, any non-zero count is only interesting for the tracepoint of
mm_compaction_migratepages events, because after that all remaining
unmigrated pages are put back and their count is set to 0.

This patch therefore removes update_nr_listpages() completely, and changes
the tracepoint definition so that the manual counting is done only when
the tracepoint is enabled, and only when migrate_pages() returns a
negative error code.

Furthermore, migrate_pages() and the tracepoints won't be called when
there's nothing to migrate.  This potentially avoids some wasted cycles
and reduces the volume of uninteresting mm_compaction_migratepages events
where "nr_migrated=0 nr_failed=0".  In the stress-highalloc mmtest, this
was about 75% of the events.  The mm_compaction_isolate_migratepages event
is better for determining that nothing was isolated for migration, and
this one was just duplicating the info.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:07 -07:00

134 lines
2.9 KiB
C

#undef TRACE_SYSTEM
#define TRACE_SYSTEM compaction
#if !defined(_TRACE_COMPACTION_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_COMPACTION_H
#include <linux/types.h>
#include <linux/list.h>
#include <linux/tracepoint.h>
#include <trace/events/gfpflags.h>
DECLARE_EVENT_CLASS(mm_compaction_isolate_template,
TP_PROTO(unsigned long nr_scanned,
unsigned long nr_taken),
TP_ARGS(nr_scanned, nr_taken),
TP_STRUCT__entry(
__field(unsigned long, nr_scanned)
__field(unsigned long, nr_taken)
),
TP_fast_assign(
__entry->nr_scanned = nr_scanned;
__entry->nr_taken = nr_taken;
),
TP_printk("nr_scanned=%lu nr_taken=%lu",
__entry->nr_scanned,
__entry->nr_taken)
);
DEFINE_EVENT(mm_compaction_isolate_template, mm_compaction_isolate_migratepages,
TP_PROTO(unsigned long nr_scanned,
unsigned long nr_taken),
TP_ARGS(nr_scanned, nr_taken)
);
DEFINE_EVENT(mm_compaction_isolate_template, mm_compaction_isolate_freepages,
TP_PROTO(unsigned long nr_scanned,
unsigned long nr_taken),
TP_ARGS(nr_scanned, nr_taken)
);
TRACE_EVENT(mm_compaction_migratepages,
TP_PROTO(unsigned long nr_all,
int migrate_rc,
struct list_head *migratepages),
TP_ARGS(nr_all, migrate_rc, migratepages),
TP_STRUCT__entry(
__field(unsigned long, nr_migrated)
__field(unsigned long, nr_failed)
),
TP_fast_assign(
unsigned long nr_failed = 0;
struct list_head *page_lru;
/*
* migrate_pages() returns either a non-negative number
* with the number of pages that failed migration, or an
* error code, in which case we need to count the remaining
* pages manually
*/
if (migrate_rc >= 0)
nr_failed = migrate_rc;
else
list_for_each(page_lru, migratepages)
nr_failed++;
__entry->nr_migrated = nr_all - nr_failed;
__entry->nr_failed = nr_failed;
),
TP_printk("nr_migrated=%lu nr_failed=%lu",
__entry->nr_migrated,
__entry->nr_failed)
);
TRACE_EVENT(mm_compaction_begin,
TP_PROTO(unsigned long zone_start, unsigned long migrate_start,
unsigned long free_start, unsigned long zone_end),
TP_ARGS(zone_start, migrate_start, free_start, zone_end),
TP_STRUCT__entry(
__field(unsigned long, zone_start)
__field(unsigned long, migrate_start)
__field(unsigned long, free_start)
__field(unsigned long, zone_end)
),
TP_fast_assign(
__entry->zone_start = zone_start;
__entry->migrate_start = migrate_start;
__entry->free_start = free_start;
__entry->zone_end = zone_end;
),
TP_printk("zone_start=%lu migrate_start=%lu free_start=%lu zone_end=%lu",
__entry->zone_start,
__entry->migrate_start,
__entry->free_start,
__entry->zone_end)
);
TRACE_EVENT(mm_compaction_end,
TP_PROTO(int status),
TP_ARGS(status),
TP_STRUCT__entry(
__field(int, status)
),
TP_fast_assign(
__entry->status = status;
),
TP_printk("status=%d", __entry->status)
);
#endif /* _TRACE_COMPACTION_H */
/* This part must be outside protection */
#include <trace/define_trace.h>