| 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.rst). |
| |
| 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 shows how many objects have been |
| allocated using the fast path. It can be written to clear the |
| current count. |
| 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 shows 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. It can be written to clear the current |
| count. |
| 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 shows how many times the per-cpu freelist |
| was empty but there were objects available as the result of |
| remote cpu frees. It can be written to clear the current count. |
| 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 shows how many times a new slab had to |
| be allocated from the page allocator. It can be written to |
| clear the current count. |
| 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 shows how many objects have been |
| allocated using the slow path because of a refill or |
| allocation from a partial or new slab. It can be written to |
| clear the current count. |
| 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/cache_dma32 |
| Date: December 2018 |
| KernelVersion: 4.21 |
| Contact: Nicolas Boichat <drinkcat@chromium.org> |
| Description: |
| The cache_dma32 file is read-only and specifies whether objects |
| are from ZONE_DMA32. |
| Available when CONFIG_ZONE_DMA32 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 shows 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. It can be written to clear the |
| current count. |
| 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 deactivate_empty file shows how many times an empty cpu slab |
| was deactivated. It can be written to clear the current count. |
| 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 deactivate_full file shows how many times a full cpu slab |
| was deactivated. It can be written to clear the current count. |
| 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 deactivate_remote_frees file shows how many times a cpu slab |
| has been deactivated and contained free objects that were freed |
| remotely. It can be written to clear the current count. |
| 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 deactivate_to_head file shows how many times a partial cpu |
| slab was deactivated and added to the head of its node's partial |
| list. It can be written to clear the current count. |
| 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 deactivate_to_tail file shows how many times a partial cpu |
| slab was deactivated and added to the tail of its node's partial |
| list. It can be written to clear the current count. |
| 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 free_add_partial file shows how many times an object has |
| been freed in a full slab so that it had to added to its node's |
| partial list. It can be written to clear the current count. |
| 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.rst). |
| |
| 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 shows how many objects have been freed |
| using the fast path because it was an object from the cpu slab. |
| It can be written to clear the current count. |
| 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 shows how many objects have been freed to |
| a frozen slab (i.e. a remote cpu slab). It can be written to |
| clear the current count. |
| 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 free_remove_partial file shows 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. It can be written to clear the current |
| count. |
| 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 shows how many times an empty slab has been |
| freed back to the page allocator. It can be written to clear |
| the current count. |
| 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 shows how many objects have been freed |
| using the slow path (i.e. to a full or partial slab). It can |
| be written to clear the current count. |
| 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. |
| When debug_guardpage_minorder=N (N > 0) parameter is specified |
| (see Documentation/admin-guide/kernel-parameters.rst), the minimum possible |
| order is used and this sysfs entry can not be used to change |
| the order at run time. |
| |
| 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 order_fallback file shows 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. It can be written to |
| clear the current count. |
| 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. |
