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

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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 zsmalloc
-------- ========
This allocator is designed for use with zram. Thus, the allocator is This allocator is designed for use with zram. Thus, the allocator is
supposed to work well under low memory conditions. In particular, it 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(). unmapped using zs_unmap_object().
stat stat
---- ====
With CONFIG_ZSMALLOC_STAT, we could see zsmalloc internal information via 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 class size almost_full almost_empty obj_allocated obj_used pages_used pages_per_zspage
.. ...
.. ...
9 176 0 1 186 129 8 4 9 176 0 1 186 129 8 4
10 192 1 0 2880 2872 135 3 10 192 1 0 2880 2872 135 3
11 208 0 1 819 795 42 2 11 208 0 1 819 795 42 2
12 224 0 1 219 159 12 4 12 224 0 1 219 159 12 4
.. ...
.. ...
class: index class
size: object size zspage stores index
almost_empty: the number of ZS_ALMOST_EMPTY zspages(see below) size
almost_full: the number of ZS_ALMOST_FULL zspages(see below) object size zspage stores
obj_allocated: the number of objects allocated almost_empty
obj_used: the number of objects allocated to the user the number of ZS_ALMOST_EMPTY zspages(see below)
pages_used: the number of pages allocated for the class almost_full
pages_per_zspage: the number of 0-order pages to make a zspage 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: We assign a zspage to ZS_ALMOST_EMPTY fullness group when n <= N / f, where
n <= N / f, where
n = number of allocated objects * n = number of allocated objects
N = total number of objects zspage can store * N = total number of objects zspage can store
f = fullness_threshold_frac(ie, 4 at the moment) * f = fullness_threshold_frac(ie, 4 at the moment)
Similarly, we assign zspage to: Similarly, we assign zspage to:
ZS_ALMOST_FULL when n > N / f
ZS_EMPTY when n == 0 * ZS_ALMOST_FULL when n > N / f
ZS_FULL when n == N * ZS_EMPTY when n == 0
* ZS_FULL when n == N