Documentation/trace/events-kmem.rst

8   - Slab allocation of small objects of unknown type (kmalloc)
9   - Slab allocation of small objects of known type
10   - Page allocation
11   - Per-CPU Allocator Activity
12   - External Fragmentation
40 These events are similar in usage to the kmalloc-related events except that
50   mm_page_alloc_zone_locked page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
56 the per-CPU allocator (high performance) or the buddy allocator.
60 amounts of activity imply high activity on the zone->lock. Taking this lock
72 contention on the lruvec->lru_lock.
74 4. Per-CPU Allocator Activity
78   mm_page_alloc_zone_locked	page=%p pfn=%lu order=%u migratetype=%d cpu=%d percpu_refill=%d
79   mm_page_pcpu_drain		page=%p pfn=%lu order=%d cpu=%d migratetype=%d
81 In front of the page allocator is a per-cpu page allocator. It exists only
82 for order-0 pages, reduces contention on the zone->lock and reduces the
85 When a per-CPU list is empty or pages of the wrong type are allocated,
86 the zone->lock will be taken once and the per-CPU list refilled. The event
90 When the per-CPU list is too full, a number of pages are freed, each one
95 consecutively imply the zone->lock being taken once. Large amounts of per-CPU
97 is being concentrated in one place. It could also indicate that the per-CPU
98 lists should be a larger size. Finally, large amounts of refills on one CPU
101 can be allocated and freed on the same CPU through some algorithm change.
109 External fragmentation affects whether a high-order allocation will be
116 high-order allocations will start failing at some time in the future. One