SLABINFO
NAME SYNOPSIS DESCRIPTION AVAILABILITY FILES
/proc/slabinfo - Kernel slab allocator statistics
cat /proc/slabinfo
Frequently used objects in the Linux kernel (buffer heads, inodes, dentries, etc) have their own cache. The file /proc/slabinfo gives statistics. For example
% cat /proc/slabinfo slabinfo - version: 1.1 kmem_cache 60 78 100 2 2 1 blkdev_requests 5120 5120 96 128 128 1 mnt_cache 20 40 96 1 1 1 inode_cache 7005 14792 480 1598 1849 1 dentry_cache 5469 5880 128 183 196 1 filp 726 760 96 19 19 1 buffer_head 67131 71240 96 1776 1781 1 vm_area_struct 1204 1652 64 23 28 1 ... size-8192 1 17 8192 1 17 2 size-4096 41 73 4096 41 73 1 ...
For each slab cache the cache name, the number of currently active objects, the total number of available objects, the size of each object in bytes, the number of pages with at least one active object, the total number of allocated pages, and the number of pages per slab are given.
Note that because of object alignment and slab cache overhead, objects are not normally packed tightly into pages. Pages with even one in-use object are considered in-use and cannot be freed.
Kernels compiled with slab cache statistics will also have
SMP systems will also have
If both slab cache statistics and SMP are defined, there will be four additional columns, reporting the per-CPU cache statistics. The first two are the per-CPU cache allocation hit and miss counts: the number of times an object was or was not available in the per-CPU cache for allocation. The next two are the per-CPU cache free hit and miss counts: the number of times a freed object could or could not fit within the per-CPU cache limit, before flushing objects to the global cache.
It is possible to tune the SMP per-CPU slab cache limit and batchcount via:
echo cache_name limit batchcount
/proc/slabinfo exists since Linux 2.1.23. SMP per-CPU caches exist since Linux 2.4.0-test3.
2 pages link to slabinfo(5):
