What: /sys/kernel/slab Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The /sys/kernel/slab directory contains a snapshot of the internal state of the SLUB allocator for each cache. Certain files may be modified to change the behavior of the cache (and any cache it aliases, if any). Users: kernel memory tuning tools What: /sys/kernel/slab/cache/aliases Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The aliases file is read-only and specifies how many caches have merged into this cache. What: /sys/kernel/slab/cache/align Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The align file is read-only and specifies the cache's object alignment in bytes. What: /sys/kernel/slab/cache/alloc_calls Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The alloc_calls file is read-only and lists the kernel code locations from which allocations for this cache were performed. The alloc_calls file only contains information if debugging is enabled for that cache (see Documentation/vm/slub.txt). What: /sys/kernel/slab/cache/alloc_fastpath Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The alloc_fastpath file is read-only and specifies how many objects have been allocated using the fast path. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/alloc_from_partial Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The alloc_from_partial file is read-only and specifies how many times a cpu slab has been full and it has been refilled by using a slab from the list of partially used slabs. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/alloc_refill Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The alloc_refill file is read-only and specifies how many times the per-cpu freelist was empty but there were objects available as the result of remote cpu frees. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/alloc_slab Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The alloc_slab file is read-only and specifies how many times a new slab had to be allocated from the page allocator. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/alloc_slowpath Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The alloc_slowpath file is read-only and specifies how many objects have been allocated using the slow path because of a refill or allocation from a partial or new slab. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/cache_dma Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The cache_dma file is read-only and specifies whether objects are from ZONE_DMA. Available when CONFIG_ZONE_DMA is enabled. What: /sys/kernel/slab/cache/cpu_slabs Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The cpu_slabs file is read-only and displays how many cpu slabs are active and their NUMA locality. What: /sys/kernel/slab/cache/cpuslab_flush Date: April 2009 KernelVersion: 2.6.31 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file cpuslab_flush is read-only and specifies how many times a cache's cpu slabs have been flushed as the result of destroying or shrinking a cache, a cpu going offline, or as the result of forcing an allocation from a certain node. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/ctor Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The ctor file is read-only and specifies the cache's object constructor function, which is invoked for each object when a new slab is allocated. What: /sys/kernel/slab/cache/deactivate_empty Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file deactivate_empty is read-only and specifies how many times an empty cpu slab was deactivated. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/deactivate_full Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file deactivate_full is read-only and specifies how many times a full cpu slab was deactivated. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/deactivate_remote_frees Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file deactivate_remote_frees is read-only and specifies how many times a cpu slab has been deactivated and contained free objects that were freed remotely. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/deactivate_to_head Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file deactivate_to_head is read-only and specifies how many times a partial cpu slab was deactivated and added to the head of its node's partial list. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/deactivate_to_tail Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file deactivate_to_tail is read-only and specifies how many times a partial cpu slab was deactivated and added to the tail of its node's partial list. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/destroy_by_rcu Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The destroy_by_rcu file is read-only and specifies whether slabs (not objects) are freed by rcu. What: /sys/kernel/slab/cache/free_add_partial Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file free_add_partial is read-only and specifies how many times an object has been freed in a full slab so that it had to added to its node's partial list. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_calls Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The free_calls file is read-only and lists the locations of object frees if slab debugging is enabled (see Documentation/vm/slub.txt). What: /sys/kernel/slab/cache/free_fastpath Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The free_fastpath file is read-only and specifies how many objects have been freed using the fast path because it was an object from the cpu slab. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_frozen Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The free_frozen file is read-only and specifies how many objects have been freed to a frozen slab (i.e. a remote cpu slab). Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_remove_partial Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file free_remove_partial is read-only and specifies how many times an object has been freed to a now-empty slab so that it had to be removed from its node's partial list. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_slab Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The free_slab file is read-only and specifies how many times an empty slab has been freed back to the page allocator. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/free_slowpath Date: February 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The free_slowpath file is read-only and specifies how many objects have been freed using the slow path (i.e. to a full or partial slab). Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/hwcache_align Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The hwcache_align file is read-only and specifies whether objects are aligned on cachelines. What: /sys/kernel/slab/cache/min_partial Date: February 2009 KernelVersion: 2.6.30 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, David Rientjes <rientjes@google.com> Description: The min_partial file specifies how many empty slabs shall remain on a node's partial list to avoid the overhead of allocating new slabs. Such slabs may be reclaimed by utilizing the shrink file. What: /sys/kernel/slab/cache/object_size Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The object_size file is read-only and specifies the cache's object size. What: /sys/kernel/slab/cache/objects Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The objects file is read-only and displays how many objects are active and from which nodes they are from. What: /sys/kernel/slab/cache/objects_partial Date: April 2008 KernelVersion: 2.6.26 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The objects_partial file is read-only and displays how many objects are on partial slabs and from which nodes they are from. What: /sys/kernel/slab/cache/objs_per_slab Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file objs_per_slab is read-only and specifies how many objects may be allocated from a single slab of the order specified in /sys/kernel/slab/cache/order. What: /sys/kernel/slab/cache/order Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The order file specifies the page order at which new slabs are allocated. It is writable and can be changed to increase the number of objects per slab. If a slab cannot be allocated because of fragmentation, SLUB will retry with the minimum order possible depending on its characteristics. What: /sys/kernel/slab/cache/order_fallback Date: April 2008 KernelVersion: 2.6.26 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file order_fallback is read-only and specifies how many times an allocation of a new slab has not been possible at the cache's order and instead fallen back to its minimum possible order. Available when CONFIG_SLUB_STATS is enabled. What: /sys/kernel/slab/cache/partial Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The partial file is read-only and displays how long many partial slabs there are and how long each node's list is. What: /sys/kernel/slab/cache/poison Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The poison file specifies whether objects should be poisoned when a new slab is allocated. What: /sys/kernel/slab/cache/reclaim_account Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The reclaim_account file specifies whether the cache's objects are reclaimable (and grouped by their mobility). What: /sys/kernel/slab/cache/red_zone Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The red_zone file specifies whether the cache's objects are red zoned. What: /sys/kernel/slab/cache/remote_node_defrag_ratio Date: January 2008 KernelVersion: 2.6.25 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The file remote_node_defrag_ratio specifies the percentage of times SLUB will attempt to refill the cpu slab with a partial slab from a remote node as opposed to allocating a new slab on the local node. This reduces the amount of wasted memory over the entire system but can be expensive. Available when CONFIG_NUMA is enabled. What: /sys/kernel/slab/cache/sanity_checks Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The sanity_checks file specifies whether expensive checks should be performed on free and, at minimum, enables double free checks. Caches that enable sanity_checks cannot be merged with caches that do not. What: /sys/kernel/slab/cache/shrink Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The shrink file is written when memory should be reclaimed from a cache. Empty partial slabs are freed and the partial list is sorted so the slabs with the fewest available objects are used first. What: /sys/kernel/slab/cache/slab_size Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The slab_size file is read-only and specifies the object size with metadata (debugging information and alignment) in bytes. What: /sys/kernel/slab/cache/slabs Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The slabs file is read-only and displays how long many slabs there are (both cpu and partial) and from which nodes they are from. What: /sys/kernel/slab/cache/store_user Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The store_user file specifies whether the location of allocation or free should be tracked for a cache. What: /sys/kernel/slab/cache/total_objects Date: April 2008 KernelVersion: 2.6.26 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The total_objects file is read-only and displays how many total objects a cache has and from which nodes they are from. What: /sys/kernel/slab/cache/trace Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: The trace file specifies whether object allocations and frees should be traced. What: /sys/kernel/slab/cache/validate Date: May 2007 KernelVersion: 2.6.22 Contact: Pekka Enberg <penberg@cs.helsinki.fi>, Christoph Lameter <cl@linux-foundation.org> Description: Writing to the validate file causes SLUB to traverse all of its cache's objects and check the validity of metadata.
