{
    "mode": "man",
    "parameter": "slabinfo",
    "section": "5",
    "url": "https://www.chedong.com/phpMan.php/man/slabinfo/5/json",
    "generated": "2026-05-30T08:15:59Z",
    "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",
            "subsections": []
        },
        "COLOPHON": {
            "content": "This page is part of release 5.10 of the Linux  man-pages  project.   A  description  of  the\nproject,  information about reporting bugs, and the latest version of this page, can be found\nat https://www.kernel.org/doc/man-pages/.\n\n\n\n2020-11-01                                  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"
        }
    ]
}