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51e95bed62
Adds documentation for the slub ABI. This is placed in the `testing' directory since the meanings of these files are still subject to change as slub is developed. Acked-by: Christoph Lameter <cl@linux-foundation.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
480 lines
16 KiB
Plaintext
480 lines
16 KiB
Plaintext
What: /sys/kernel/slab
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The /sys/kernel/slab directory contains a snapshot of the
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internal state of the SLUB allocator for each cache. Certain
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files may be modified to change the behavior of the cache (and
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any cache it aliases, if any).
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Users: kernel memory tuning tools
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What: /sys/kernel/slab/cache/aliases
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The aliases file is read-only and specifies how many caches
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have merged into this cache.
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What: /sys/kernel/slab/cache/align
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The align file is read-only and specifies the cache's object
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alignment in bytes.
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What: /sys/kernel/slab/cache/alloc_calls
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The alloc_calls file is read-only and lists the kernel code
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locations from which allocations for this cache were performed.
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The alloc_calls file only contains information if debugging is
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enabled for that cache (see Documentation/vm/slub.txt).
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What: /sys/kernel/slab/cache/alloc_fastpath
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The alloc_fastpath file is read-only and specifies how many
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objects have been allocated using the fast path.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/alloc_from_partial
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The alloc_from_partial file is read-only and specifies how
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many times a cpu slab has been full and it has been refilled
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by using a slab from the list of partially used slabs.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/alloc_refill
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The alloc_refill file is read-only and specifies how many
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times the per-cpu freelist was empty but there were objects
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available as the result of remote cpu frees.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/alloc_slab
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The alloc_slab file is read-only and specifies how many times
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a new slab had to be allocated from the page allocator.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/alloc_slowpath
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The alloc_slowpath file is read-only and specifies how many
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objects have been allocated using the slow path because of a
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refill or allocation from a partial or new slab.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/cache_dma
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The cache_dma file is read-only and specifies whether objects
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are from ZONE_DMA.
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Available when CONFIG_ZONE_DMA is enabled.
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What: /sys/kernel/slab/cache/cpu_slabs
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The cpu_slabs file is read-only and displays how many cpu slabs
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are active and their NUMA locality.
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What: /sys/kernel/slab/cache/cpuslab_flush
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Date: April 2009
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KernelVersion: 2.6.31
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file cpuslab_flush is read-only and specifies how many
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times a cache's cpu slabs have been flushed as the result of
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destroying or shrinking a cache, a cpu going offline, or as
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the result of forcing an allocation from a certain node.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/ctor
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The ctor file is read-only and specifies the cache's object
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constructor function, which is invoked for each object when a
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new slab is allocated.
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What: /sys/kernel/slab/cache/deactivate_empty
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file deactivate_empty is read-only and specifies how many
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times an empty cpu slab was deactivated.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/deactivate_full
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file deactivate_full is read-only and specifies how many
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times a full cpu slab was deactivated.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/deactivate_remote_frees
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file deactivate_remote_frees is read-only and specifies how
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many times a cpu slab has been deactivated and contained free
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objects that were freed remotely.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/deactivate_to_head
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file deactivate_to_head is read-only and specifies how
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many times a partial cpu slab was deactivated and added to the
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head of its node's partial list.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/deactivate_to_tail
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file deactivate_to_tail is read-only and specifies how
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many times a partial cpu slab was deactivated and added to the
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tail of its node's partial list.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/destroy_by_rcu
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The destroy_by_rcu file is read-only and specifies whether
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slabs (not objects) are freed by rcu.
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What: /sys/kernel/slab/cache/free_add_partial
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file free_add_partial is read-only and specifies how many
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times an object has been freed in a full slab so that it had to
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added to its node's partial list.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/free_calls
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The free_calls file is read-only and lists the locations of
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object frees if slab debugging is enabled (see
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Documentation/vm/slub.txt).
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What: /sys/kernel/slab/cache/free_fastpath
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The free_fastpath file is read-only and specifies how many
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objects have been freed using the fast path because it was an
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object from the cpu slab.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/free_frozen
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The free_frozen file is read-only and specifies how many
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objects have been freed to a frozen slab (i.e. a remote cpu
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slab).
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/free_remove_partial
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file free_remove_partial is read-only and specifies how
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many times an object has been freed to a now-empty slab so
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that it had to be removed from its node's partial list.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/free_slab
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The free_slab file is read-only and specifies how many times an
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empty slab has been freed back to the page allocator.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/free_slowpath
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Date: February 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The free_slowpath file is read-only and specifies how many
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objects have been freed using the slow path (i.e. to a full or
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partial slab).
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/hwcache_align
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The hwcache_align file is read-only and specifies whether
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objects are aligned on cachelines.
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What: /sys/kernel/slab/cache/min_partial
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Date: February 2009
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KernelVersion: 2.6.30
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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David Rientjes <rientjes@google.com>
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Description:
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The min_partial file specifies how many empty slabs shall
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remain on a node's partial list to avoid the overhead of
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allocating new slabs. Such slabs may be reclaimed by utilizing
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the shrink file.
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What: /sys/kernel/slab/cache/object_size
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The object_size file is read-only and specifies the cache's
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object size.
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What: /sys/kernel/slab/cache/objects
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The objects file is read-only and displays how many objects are
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active and from which nodes they are from.
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What: /sys/kernel/slab/cache/objects_partial
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Date: April 2008
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KernelVersion: 2.6.26
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The objects_partial file is read-only and displays how many
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objects are on partial slabs and from which nodes they are
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from.
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What: /sys/kernel/slab/cache/objs_per_slab
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file objs_per_slab is read-only and specifies how many
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objects may be allocated from a single slab of the order
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specified in /sys/kernel/slab/cache/order.
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What: /sys/kernel/slab/cache/order
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The order file specifies the page order at which new slabs are
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allocated. It is writable and can be changed to increase the
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number of objects per slab. If a slab cannot be allocated
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because of fragmentation, SLUB will retry with the minimum order
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possible depending on its characteristics.
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What: /sys/kernel/slab/cache/order_fallback
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Date: April 2008
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KernelVersion: 2.6.26
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file order_fallback is read-only and specifies how many
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times an allocation of a new slab has not been possible at the
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cache's order and instead fallen back to its minimum possible
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order.
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Available when CONFIG_SLUB_STATS is enabled.
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What: /sys/kernel/slab/cache/partial
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The partial file is read-only and displays how long many
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partial slabs there are and how long each node's list is.
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What: /sys/kernel/slab/cache/poison
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The poison file specifies whether objects should be poisoned
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when a new slab is allocated.
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What: /sys/kernel/slab/cache/reclaim_account
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The reclaim_account file specifies whether the cache's objects
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are reclaimable (and grouped by their mobility).
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What: /sys/kernel/slab/cache/red_zone
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The red_zone file specifies whether the cache's objects are red
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zoned.
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What: /sys/kernel/slab/cache/remote_node_defrag_ratio
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Date: January 2008
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KernelVersion: 2.6.25
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The file remote_node_defrag_ratio specifies the percentage of
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times SLUB will attempt to refill the cpu slab with a partial
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slab from a remote node as opposed to allocating a new slab on
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the local node. This reduces the amount of wasted memory over
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the entire system but can be expensive.
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Available when CONFIG_NUMA is enabled.
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What: /sys/kernel/slab/cache/sanity_checks
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The sanity_checks file specifies whether expensive checks
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should be performed on free and, at minimum, enables double free
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checks. Caches that enable sanity_checks cannot be merged with
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caches that do not.
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What: /sys/kernel/slab/cache/shrink
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The shrink file is written when memory should be reclaimed from
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a cache. Empty partial slabs are freed and the partial list is
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sorted so the slabs with the fewest available objects are used
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first.
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What: /sys/kernel/slab/cache/slab_size
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The slab_size file is read-only and specifies the object size
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with metadata (debugging information and alignment) in bytes.
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What: /sys/kernel/slab/cache/slabs
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The slabs file is read-only and displays how long many slabs
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there are (both cpu and partial) and from which nodes they are
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from.
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What: /sys/kernel/slab/cache/store_user
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The store_user file specifies whether the location of
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allocation or free should be tracked for a cache.
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What: /sys/kernel/slab/cache/total_objects
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Date: April 2008
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KernelVersion: 2.6.26
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The total_objects file is read-only and displays how many total
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objects a cache has and from which nodes they are from.
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What: /sys/kernel/slab/cache/trace
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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The trace file specifies whether object allocations and frees
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should be traced.
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What: /sys/kernel/slab/cache/validate
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Date: May 2007
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KernelVersion: 2.6.22
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Contact: Pekka Enberg <penberg@cs.helsinki.fi>,
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Christoph Lameter <cl@linux-foundation.org>
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Description:
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Writing to the validate file causes SLUB to traverse all of its
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cache's objects and check the validity of metadata.
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