[PATCH V2 2/2] Documentation: filesystems: introduce proc/slabinfo to users

[Fangzheng Zhang <fangzheng.zhang@unisoc.com>]

Supplement slabinfo-version 2.2 details in proc.rst, so that
users can have the status of slabinfo at a glance. And mark
the optimization work that will be performed on proc/slabinfo
in the next step.

Signed-off-by: Fangzheng Zhang <fangzheng.zhang@unisoc.com>
---
 Documentation/filesystems/proc.rst | 33 ++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 104c6d047d9b..89ab92f6be2d 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -892,6 +892,39 @@ Linux uses  slab  pools for memory management above page level in version 2.2.
 Commonly used  objects  have  their  own  slab  pool (such as network buffers,
 directory cache, and so on).
 
+Example output. You can have all of these fields in slabinfo - version: 2.2.
+
+::
+
+    > cat /proc/slabinfo
+
+    slabinfo - version: 2.2
+    # name            <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> : tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_slabs> <sharedavail> <slabreclaim>
+    zspage              2240   2240     72   56    1 : tunables    0    0    0 : slabdata     40     40      0      0
+    zs_handle          17408  17408      8  512    1 : tunables    0    0    0 : slabdata     34     34      0      0
+    f2fs_xattr_entry-254:48    312    312    208   39    2 : tunables    0    0    0 : slabdata      8      8      0      1
+    imsbr_flow           102    102     80   51    1 : tunables    0    0    0 : slabdata      2      2      0      0
+    ......
+    ext4_groupinfo_4k    312    312    208   39    2 : tunables    0    0    0 : slabdata      8      8      0      1
+    dm_verity_fec_buffers      8      8   4048    8    8 : tunables    0    0    0 : slabdata      1      1      0      0
+    dm_bufio_buffer       28     28    144   28    1 : tunables    0    0    0 : slabdata      1      1      0      1
+    ......
+    kernfs_iattrs_cache   4010   4116     96   42    1 : tunables    0    0    0 : slabdata     98     98      0      0
+    kernfs_node_cache  67169  67232    128   32    1 : tunables    0    0    0 : slabdata   2101   2101      0      0
+    mnt_cache           5624   5700    320   25    2 : tunables    0    0    0 : slabdata    228    228      0      0
+    filp               15840  17400    320   25    2 : tunables    0    0    0 : slabdata    696    696      0      0
+    ......
+    kmalloc-32         30398  32384     32  128    1 : tunables    0    0    0 : slabdata    253    253      0      0
+    kmalloc-16         31566  31744     16  256    1 : tunables    0    0    0 : slabdata    124    124      0      0
+    kmalloc-8          51623  51712      8  512    1 : tunables    0    0    0 : slabdata    101    101      0      0
+    kmem_cache_node      416    416    128   32    1 : tunables    0    0    0 : slabdata     13     13      0      0
+    kmem_cache           416    416    256   32    2 : tunables    0    0    0 : slabdata     13     13      0      0
+
+Note, <slabreclaim> comes from the collected results in the file
+/sys/kernel/slab/$cache/reclaim_account. Next, we will mark /proc/slabinfo
+as deprecated and recommend the use of either sysfs directly or
+use of the "slabinfo" tool that we have been providing in linux/tools/mm.
+
 ::
 
     > cat /proc/buddyinfo
-- 
2.17.1