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diff --git a/Documentation/ABI/testing/sysfs-kernel-slab b/Documentation/ABI/testing/sysfs-kernel-slab new file mode 100644 index 000000000..cd5fb8fa3 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-slab @@ -0,0 +1,519 @@ +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/mm/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>/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/mm/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 used to reclaim unused slab cache + memory from a cache. Empty per-cpu or partial slabs + are freed and the partial list is sorted so the slabs + with the fewest available objects are used first. + It only accepts a value of "1" on write for shrinking + the cache. Other input values are considered invalid. + Shrinking slab caches might be expensive and can + adversely impact other running applications. So it + should be used with care. + +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. + +What: /sys/kernel/slab/<cache>/usersize +Date: Jun 2017 +Contact: David Windsor <dave@nullcore.net> +Description: + The usersize file is read-only and contains the usercopy + region size. + +What: /sys/kernel/slab/<cache>/slabs_cpu_partial +Date: Aug 2011 +Contact: Christoph Lameter <cl@linux.com> +Description: + This read-only file shows the number of partialli allocated + frozen slabs. + +What: /sys/kernel/slab/<cache>/cpu_partial +Date: Aug 2011 +Contact: Christoph Lameter <cl@linux.com> +Description: + This read-only file shows the number of per cpu partial + pages to keep around. |