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mm: numa: trace tasks that fail migration due to rate limiting

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A low local/remote numa hinting fault ratio is potentially explained by
failed migrations.  This patch adds a tracepoint that fires when
migration fails due to migration rate limitation.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman 2014-01-21 15:51:01 -08:00 committed by Linus Torvalds
parent 1c5e9c27cb
commit af1839d722
2 changed files with 30 additions and 1 deletions
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26
include/trace/events/migrate.h
View File

@ -45,6 +45,32 @@ TRACE_EVENT(mm_migrate_pages,
__print_symbolic(__entry->reason, MIGRATE_REASON))
);
TRACE_EVENT(mm_numa_migrate_ratelimit,
TP_PROTO(struct task_struct *p, int dst_nid, unsigned long nr_pages),
TP_ARGS(p, dst_nid, nr_pages),
TP_STRUCT__entry(
__array( char, comm, TASK_COMM_LEN)
__field( pid_t, pid)
__field( int, dst_nid)
__field( unsigned long, nr_pages)
),
TP_fast_assign(
memcpy(__entry->comm, p->comm, TASK_COMM_LEN);
__entry->pid = p->pid;
__entry->dst_nid = dst_nid;
__entry->nr_pages = nr_pages;
),
TP_printk("comm=%s pid=%d dst_nid=%d nr_pages=%lu",
__entry->comm,
__entry->pid,
__entry->dst_nid,
__entry->nr_pages)
);
#endif /* _TRACE_MIGRATE_H */
/* This part must be outside protection */

5
mm/migrate.c
View File

@ -1614,8 +1614,11 @@ static bool numamigrate_update_ratelimit(pg_data_t *pgdat,
msecs_to_jiffies(migrate_interval_millisecs);
spin_unlock(&pgdat->numabalancing_migrate_lock);
}
if (pgdat->numabalancing_migrate_nr_pages > ratelimit_pages)
if (pgdat->numabalancing_migrate_nr_pages > ratelimit_pages) {
trace_mm_numa_migrate_ratelimit(current, pgdat->node_id,
nr_pages);
return true;
}
/*
* This is an unlocked non-atomic update so errors are possible.