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docs/vm: zsmalloc.txt: convert to ReST format 

Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Mike Rapoport 2018-03-21 21:22:45 +02:00 committed by Jonathan Corbet
parent 44bc09eb3e
commit 2a05c58bf9
1 changed files with 36 additions and 24 deletions
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60
Documentation/vm/zsmalloc.txt
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@ -1,5 +1,8 @@
.. _zsmalloc:
========
zsmalloc
--------
========
This allocator is designed for use with zram. Thus, the allocator is
supposed to work well under low memory conditions. In particular, it
@ -31,40 +34,49 @@ be mapped using zs_map_object() to get a usable pointer and subsequently
unmapped using zs_unmap_object().
stat
----
====
With CONFIG_ZSMALLOC_STAT, we could see zsmalloc internal information via
/sys/kernel/debug/zsmalloc/<user name>. Here is a sample of stat output:
``/sys/kernel/debug/zsmalloc/<user name>``. Here is a sample of stat output::
# cat /sys/kernel/debug/zsmalloc/zram0/classes
# cat /sys/kernel/debug/zsmalloc/zram0/classes
class size almost_full almost_empty obj_allocated obj_used pages_used pages_per_zspage
..
..
...
...
9 176 0 1 186 129 8 4
10 192 1 0 2880 2872 135 3
11 208 0 1 819 795 42 2
12 224 0 1 219 159 12 4
..
..
...
...
class: index
size: object size zspage stores
almost_empty: the number of ZS_ALMOST_EMPTY zspages(see below)
almost_full: the number of ZS_ALMOST_FULL zspages(see below)
obj_allocated: the number of objects allocated
obj_used: the number of objects allocated to the user
pages_used: the number of pages allocated for the class
pages_per_zspage: the number of 0-order pages to make a zspage
class
index
size
object size zspage stores
almost_empty
the number of ZS_ALMOST_EMPTY zspages(see below)
almost_full
the number of ZS_ALMOST_FULL zspages(see below)
obj_allocated
the number of objects allocated
obj_used
the number of objects allocated to the user
pages_used
the number of pages allocated for the class
pages_per_zspage
the number of 0-order pages to make a zspage
We assign a zspage to ZS_ALMOST_EMPTY fullness group when:
n <= N / f, where
n = number of allocated objects
N = total number of objects zspage can store
f = fullness_threshold_frac(ie, 4 at the moment)
We assign a zspage to ZS_ALMOST_EMPTY fullness group when n <= N / f, where
* n = number of allocated objects
* N = total number of objects zspage can store
* f = fullness_threshold_frac(ie, 4 at the moment)
Similarly, we assign zspage to:
ZS_ALMOST_FULL when n > N / f
ZS_EMPTY when n == 0
ZS_FULL when n == N
* ZS_ALMOST_FULL when n > N / f
* ZS_EMPTY when n == 0
* ZS_FULL when n == N