{
    "mode": "man",
    "parameter": "slabinfo",
    "section": "5",
    "url": "https://www.chedong.com/phpMan.php/man/slabinfo/5/json",
    "generated": "2026-09-17T21:11:13Z",
    "synopsis": "",
    "sections": {
        "NAME": {
            "content": "slabinfo - kernel slab allocator statistics\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "",
            "subsections": [
                {
                    "name": "cat /proc/slabinfo",
                    "content": ""
                }
            ]
        },
        "DESCRIPTION": {
            "content": "Frequently  used  objects  in  the  Linux kernel (buffer heads, inodes, dentries, etc.)  have\ntheir own cache.  The file /proc/slabinfo gives statistics on these  caches.   The  following\n(edited) output shows an example of the contents of this file:\n\n$ sudo cat /proc/slabinfo\nslabinfo - version: 2.1\n# name    <activeobjs> <numobjs> <objsize> <objperslab> <pagesperslab> ...\nsigqueue      100  100  160   25  1 : tunables  0  0  0 : slabdata   4   4  0\nsighandcache 355   405 2112  15  8 : tunables  0  0  0 : slabdata  27  27  0\nkmalloc-8192   96   96  8192   4  8 : tunables  0  0  0 : slabdata  24  24  0\n...\n\nThe first line of output includes a version number, which allows an application that is read‐\ning  the  file  to  handle changes in the file format.  (See VERSIONS, below.)  The next line\nlists the names of the columns in the remaining lines.\n\nEach of the remaining lines displays information about  a  specified  cache.   Following  the\ncache name, the output shown in each line shows three components for each cache:\n\n•  statistics\n\n•  tunables\n\n•  slabdata\n\nThe statistics are as follows:\n\nactiveobjs\nThe number of objects that are currently active (i.e., in use).\n\nnumobjs\nThe  total  number of allocated objects (i.e., objects that are both in use and not in\nuse).\n\nobjsize\nThe size of objects in this slab, in bytes.\n\nobjperslab\nThe number of objects stored in each slab.\n\npagesperslab\nThe number of pages allocated for each slab.\n\nThe tunables entries in each line show tunable parameters for the corresponding cache.   When\nusing  the  default  SLUB  allocator,  there  are no tunables, the /proc/slabinfo file is not\nwritable, and the value 0 is shown in these fields.  When using the older SLAB allocator, the\ntunables for a particular cache can be  set  by  writing  lines  of  the  following  form  to\n/proc/slabinfo:\n\n# echo 'name limit batchcount sharedfactor' > /proc/slabinfo\n\nHere,  name  is the cache name, and limit, batchcount, and sharedfactor are integers defining\nnew values for the corresponding tunables.  The limit  value  should  be  a  positive  value,\nbatchcount  should  be a positive value that is less than or equal to limit, and sharedfactor\nshould be nonnegative.  If any of the specified values is invalid,  the  cache  settings  are\nleft unchanged.\n\nThe tunables entries in each line contain the following fields:\n\nlimit  The maximum number of objects that will be cached.\n\nbatchcount\nOn  SMP systems, this specifies the number of objects to transfer at one time when re‐\nfilling the available object list.\n\nsharedfactor\n[To be documented]\n\nThe slabdata entries in each line contain the following fields:\n\nactiveslabs\nThe number of active slabs.\n\nnumsslabs\nThe total number of slabs.\n\nsharedavail\n[To be documented]\n\nNote that because of object alignment and slab  cache  overhead,  objects  are  not  normally\npacked  tightly into pages.  Pages with even one in-use object are considered in-use and can‐\nnot be freed.\n\nKernels configured with CONFIGDEBUGSLAB will also have additional statistics fields in each\nline, and the first line of the file will contain the string \"(statistics)\".  The  statistics\nfield  include : the high water mark of active objects; the number of times objects have been\nallocated; the number of times the cache has grown (new pages added to this cache); the  num‐\nber of times the cache has been reaped (unused pages removed from this cache); and the number\nof times there was an error allocating new pages to this cache.\n",
            "subsections": []
        },
        "VERSIONS": {
            "content": "The /proc/slabinfo file first appeared in Linux 2.1.23.  The file is versioned, and over time\nthere have been a number of versions with different layouts:\n\n1.0    Present throughout the Linux 2.2.x kernel series.\n\n1.1    Present in the Linux 2.4.x kernel series.\n\n1.2    A format that was briefly present in the Linux 2.5 development series.\n\n2.0    Present in Linux 2.6.x kernels up to and including Linux 2.6.9.\n\n2.1    The current format, which first appeared in Linux 2.6.10.\n",
            "subsections": []
        },
        "NOTES": {
            "content": "Only  root  can  read  and  (if  the  kernel  was  configured  with  CONFIGSLAB)  write  the\n/proc/slabinfo file.\n\nThe total amount of memory allocated to the SLAB/SLUB cache is shown in  the  Slab  field  of\n/proc/meminfo.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "slabtop(1)\n\nThe kernel source file Documentation/vm/slub.txt and tools/vm/slabinfo.c.\n\nLinux man-pages 6.7                          2023-10-31                                  slabinfo(5)",
            "subsections": []
        }
    },
    "summary": "slabinfo - kernel slab allocator statistics",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "slabtop",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/slabtop/1/json"
        }
    ]
}