linux.git/Documentation/ABI/testing/sysfs-kernel-slab, branch master

docs: ABI: sysfs-kernel-slab: mark cpu_partial attributes deprecated

2026-07-08T16:31:27+00:00

The per-cpu slab and per-cpu partial slab mechanisms were removed when
SLUB was fully converted to per-cpu sheaves in Linux 7.0. The cpu_slabs,
slabs_cpu_partial and cpu_partial sysfs attributes were kept as stubs
that always return 0 for backwards compatibility, but their
documentation still described them as if they were functional.

Update the three descriptions to state that the attributes are
deprecated and always read 0, and note that they are retained only for
compatibility. While here, fix a "partialli" typo in the
slabs_cpu_partial description.

Signed-off-by: Seongjun Hong 
Acked-by: Harry Yoo (Oracle) 
Link: https://patch.msgid.link/20260701141755.85119-1-hsj0512@snu.ac.kr
Signed-off-by: Vlastimil Babka (SUSE)

doc: Move SLUB documentation to the admin guide

2025-06-18T11:06:26+00:00

This section is supposed to be for internal documentation, while the
document is advice for sysadmins.  Move it to the appropriate place.

Signed-off-by: Matthew Wilcox (Oracle) 
Acked-by: Harry Yoo 
Link: https://patch.msgid.link/20250611155916.2579160-2-willy@infradead.org
Signed-off-by: Vlastimil Babka

Update Christoph's Email address and make it consistent

2025-05-13T06:50:31+00:00

Use cl@gentwo.org throughout and remove the old email addresses.

Link: https://lkml.kernel.org/r/8b962f57-4d98-cbb0-cd82-b6ba456733e8@gentwo.org
Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton

docs: rename Documentation/vm to Documentation/mm

2022-06-27T19:52:53+00:00

so it will be consistent with code mm directory and with
Documentation/admin-guide/mm and won't be confused with virtual machines.

Signed-off-by: Mike Rapoport 
Suggested-by: Matthew Wilcox 
Tested-by: Ira Weiny 
Acked-by: Jonathan Corbet 
Acked-by: Wu XiangCheng

ABI: sysfs-kernel-slab: Document some stats

2021-09-28T10:48:15+00:00

Document three slab stats that were added in 2011 and 2017.

Fixes: 49e2258586b4 ("slub: per cpu cache for partial pages")
Fixes: 8eb8284b4129 ("usercopy: Prepare for usercopy whitelisting")

Signed-off-by: Mauro Carvalho Chehab 
Link: https://lore.kernel.org/r/8960435734c5aa918568ce7891171448c4d68709.1632750608.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman

ABI: sysfs-kernel-slab: use a wildcard for the cache name

2021-09-21T16:31:15+00:00

the "cache" part of the description is actually a wildcard,
as, in practice, this will use per-subsystem names:

    /sys/kernel/slab/Acpi-Namespace/align
    /sys/kernel/slab/Acpi-Operand/align
    /sys/kernel/slab/Acpi-Parse/align
...
    /sys/kernel/slab/zswap_entry/align

Signed-off-by: Mauro Carvalho Chehab 
Link: https://lore.kernel.org/r/64095cc0a38d0f675ab798d4f04d8631674b59f7.1631782432.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman

docs: ABI: cleanup several ABI documents

2020-10-30T12:14:29+00:00

There are some ABI documents that, while they don't generate
any warnings, they have issues when parsed by get_abi.pl script
on its output result.

Address them, in order to provide a clean output.

Reviewed-by: Tom Rix  # for fpga-manager
Reviewed-By: Kajol Jain # for sysfs-bus-event_source-devices-hv_gpci and sysfs-bus-event_source-devices-hv_24x7
Acked-by: Jonathan Cameron  #for IIO
Acked-by: Oded Gabbay  # for Habanalabs
Acked-by: Vaibhav Jain  # for sysfs-bus-papr-pmem
Acked-by: Cezary Rojewski  # for catpt
Acked-by: Suzuki K Poulose 
Acked-by: Ilya Dryomov  # for rbd
Acked-by: Jonathan Corbet 
Signed-off-by: Mauro Carvalho Chehab 
Link: https://lore.kernel.org/r/5bc78e5b68ed1e9e39135173857cb2e753be868f.1604042072.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman

mm, slab: extend slab/shrink to shrink all memcg caches

2019-09-24T22:54:07+00:00

Currently, a value of '1" is written to /sys/kernel/slab//shrink
file to shrink the slab by flushing out all the per-cpu slabs and free
slabs in partial lists.  This can be useful to squeeze out a bit more
memory under extreme condition as well as making the active object counts
in /proc/slabinfo more accurate.

This usually applies only to the root caches, as the SLUB_MEMCG_SYSFS_ON
option is usually not enabled and "slub_memcg_sysfs=1" not set.  Even if
memcg sysfs is turned on, it is too cumbersome and impractical to manage
all those per-memcg sysfs files in a real production system.

So there is no practical way to shrink memcg caches.  Fix this by enabling
a proper write to the shrink sysfs file of the root cache to scan all the
available memcg caches and shrink them as well.  For a non-root memcg
cache (when SLUB_MEMCG_SYSFS_ON or slub_memcg_sysfs is on), only that
cache will be shrunk when written.

On a 2-socket 64-core 256-thread arm64 system with 64k page after
a parallel kernel build, the the amount of memory occupied by slabs
before shrinking slabs were:

 # grep task_struct /proc/slabinfo
 task_struct        53137  53192   4288   61    4 : tunables    0    0
 0 : slabdata    872    872      0
 # grep "^S[lRU]" /proc/meminfo
 Slab:            3936832 kB
 SReclaimable:     399104 kB
 SUnreclaim:      3537728 kB

After shrinking slabs (by echoing "1" to all shrink files):

 # grep "^S[lRU]" /proc/meminfo
 Slab:            1356288 kB
 SReclaimable:     263296 kB
 SUnreclaim:      1092992 kB
 # grep task_struct /proc/slabinfo
 task_struct         2764   6832   4288   61    4 : tunables    0    0
 0 : slabdata    112    112      0

Link: http://lkml.kernel.org/r/20190723151445.7385-1-longman@redhat.com
Signed-off-by: Waiman Long 
Acked-by: Roman Gushchin 
Acked-by: Christoph Lameter 
Cc: Pekka Enberg 
Cc: David Rientjes 
Cc: Joonsoo Kim 
Cc: Michal Hocko 
Cc: Johannes Weiner 
Cc: Shakeel Butt 
Cc: Vladimir Davydov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

docs/vm: rename documentation files to .rst

2018-04-16T20:18:15+00:00

Signed-off-by: Mike Rapoport 
Signed-off-by: Jonathan Corbet

docs: fix locations of several documents that got moved

2016-10-24T10:12:35+00:00

The previous patch renamed several files that are cross-referenced
along the Kernel documentation. Adjust the links to point to
the right places.

Signed-off-by: Mauro Carvalho Chehab