From af1839d722c986ffeaae1e70a6ef1c75ff38dcd5 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 21 Jan 2014 15:51:01 -0800 Subject: [PATCH] mm: numa: trace tasks that fail migration due to rate limiting 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 Reviewed-by: Rik van Riel Cc: Alex Thorlton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/trace/events/migrate.h | 26 ++++++++++++++++++++++++++ mm/migrate.c | 5 ++++- 2 files changed, 30 insertions(+), 1 deletion(-) diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h index ec2a6ccfd7e5..3075ffbb9a83 100644 --- a/include/trace/events/migrate.h +++ b/include/trace/events/migrate.h @@ -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 */ diff --git a/mm/migrate.c b/mm/migrate.c index 4612bb2e3677..f9e16350d09c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -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.