Commit 2a05c58b authored by Mike Rapoport's avatar Mike Rapoport Committed by Jonathan Corbet
Browse files

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



Signed-off-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 44bc09eb

Documentation/vm/zsmalloc.txt

+36 −24
Original line number Diff line number Diff line 
.. _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



 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



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)

* 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