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Diffstat (limited to 'Documentation/trace/events-kmem.txt')
| -rw-r--r-- | Documentation/trace/events-kmem.txt | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/Documentation/trace/events-kmem.txt b/Documentation/trace/events-kmem.txt index 6ef2a86..aa82ee4 100644 --- a/Documentation/trace/events-kmem.txt +++ b/Documentation/trace/events-kmem.txt @@ -1,7 +1,7 @@ Subsystem Trace Points: kmem -The tracing system kmem captures events related to object and page allocation -within the kernel. Broadly speaking there are four major subheadings. +The kmem tracing system captures events related to object and page allocation +within the kernel. Broadly speaking there are five major subheadings. o Slab allocation of small objects of unknown type (kmalloc) o Slab allocation of small objects of known type @@ -9,7 +9,7 @@ within the kernel. Broadly speaking there are four major subheadings. o Per-CPU Allocator Activity o External Fragmentation -This document will describe what each of the tracepoints are and why they +This document describes what each of the tracepoints is and why they might be useful. 1. Slab allocation of small objects of unknown type @@ -34,7 +34,7 @@ kmem_cache_free call_site=%lx ptr=%p These events are similar in usage to the kmalloc-related events except that it is likely easier to pin the event down to a specific cache. At the time of writing, no information is available on what slab is being allocated from, -but the call_site can usually be used to extrapolate that information +but the call_site can usually be used to extrapolate that information. 3. Page allocation ================== @@ -80,9 +80,9 @@ event indicating whether it is for a percpu_refill or not. When the per-CPU list is too full, a number of pages are freed, each one which triggers a mm_page_pcpu_drain event. -The individual nature of the events are so that pages can be tracked +The individual nature of the events is so that pages can be tracked between allocation and freeing. A number of drain or refill pages that occur -consecutively imply the zone->lock being taken once. Large amounts of PCP +consecutively imply the zone->lock being taken once. Large amounts of per-CPU refills and drains could imply an imbalance between CPUs where too much work is being concentrated in one place. It could also indicate that the per-CPU lists should be a larger size. Finally, large amounts of refills on one CPU @@ -102,6 +102,6 @@ is important. Large numbers of this event implies that memory is fragmenting and high-order allocations will start failing at some time in the future. One -means of reducing the occurange of this event is to increase the size of +means of reducing the occurrence of this event is to increase the size of min_free_kbytes in increments of 3*pageblock_size*nr_online_nodes where pageblock_size is usually the size of the default hugepage size. |
