The patch titled
Subject: Documentation: document zram pages_per_pool_page attribute
has been added to the -mm mm-unstable branch. Its filename is
documentation-document-zram-pages_per_pool_page-attribute.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/documentation-document-zram-pages_per_pool_page-attribute.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: Documentation: document zram pages_per_pool_page attribute
Date: Thu, 27 Oct 2022 13:26:50 +0900
Provide a simple documentation for pages_per_pool_page ZRAM device
attribute.
Link: https://lkml.kernel.org/r/20221027042651.234524-9-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Alexey Romanov <avromanov@xxxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/Documentation/admin-guide/blockdev/zram.rst~documentation-document-zram-pages_per_pool_page-attribute
+++ a/Documentation/admin-guide/blockdev/zram.rst
@@ -112,7 +112,29 @@ to list all of them using, for instance,
method. This, however, has an advantage of permitting the usage of
custom crypto compression modules (implementing S/W or H/W compression).
-4) Set Disksize
+4) Set pages per-pool page limit: Optional
+==========================================
+
+zsmalloc pages can consist of up to ZS_DEFAULT_PAGES_PER_ZSPAGE (single)
+physical pages. The exact number is calculated for each zsmalloc size
+class during zsmalloc pool creation. ZRAM provides pages_per_pool_page
+device attribute that lets one adjust that limit (maximum possible value
+is ZS_MAX_PAGES_PER_ZSPAGE). The default limit is considered to be good
+enough, so tweak this value only when the changes in zsmalloc size classes
+characteristics are beneficial for your data patterns. The limit on the
+pages per zspages (currently) should be in [1,16] range; default value
+is 4.
+
+Examples::
+
+ #show current zsmalloc pages per-pool page limit
+ cat /sys/block/zramX/pages_per_pool_page
+ 4
+
+ #set zsmalloc pages per-pool page limit
+ echo 8 > /sys/block/zramX/pages_per_pool_page
+
+5) Set Disksize
===============
Set disk size by writing the value to sysfs node 'disksize'.
@@ -132,7 +154,7 @@ There is little point creating a zram of
since we expect a 2:1 compression ratio. Note that zram uses about 0.1% of the
size of the disk when not in use so a huge zram is wasteful.
-5) Set memory limit: Optional
+6) Set memory limit: Optional
=============================
Set memory limit by writing the value to sysfs node 'mem_limit'.
@@ -151,7 +173,7 @@ Examples::
# To disable memory limit
echo 0 > /sys/block/zram0/mem_limit
-6) Activate
+7) Activate
===========
::
@@ -162,7 +184,7 @@ Examples::
mkfs.ext4 /dev/zram1
mount /dev/zram1 /tmp
-7) Add/remove zram devices
+8) Add/remove zram devices
==========================
zram provides a control interface, which enables dynamic (on-demand) device
@@ -182,7 +204,7 @@ execute::
echo X > /sys/class/zram-control/hot_remove
-8) Stats
+9) Stats
========
Per-device statistics are exported as various nodes under /sys/block/zram<id>/
@@ -283,15 +305,15 @@ a single line of text and contains the f
Unit: 4K bytes
============== =============================================================
-9) Deactivate
-=============
+10) Deactivate
+==============
::
swapoff /dev/zram0
umount /dev/zram1
-10) Reset
+11) Reset
=========
Write any positive value to 'reset' sysfs node::
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
zram-preparation-for-multi-zcomp-support.patch
zram-add-recompression-algorithm-sysfs-knob.patch
zram-factor-out-wb-and-non-wb-zram-read-functions.patch
zram-introduce-recompress-sysfs-knob.patch
documentation-add-recompression-documentation.patch
zram-add-recompression-algorithm-choice-to-kconfig.patch
zram-add-recompress-flag-to-read_block_state.patch
zram-clarify-writeback_store-comment.patch
zram-use-is_err_value-to-check-for-zs_malloc-errors.patch
zsmalloc-turn-zspage-order-into-runtime-variable.patch
zsmalloc-move-away-from-page-order-defines.patch
zsmalloc-make-huge-class-watermark-zs_pool-member.patch
zram-huge-size-watermark-cannot-be-global.patch
zsmalloc-pass-limit-on-pages-per-zspage-to-zs_create_pool.patch
zram-add-pages_per_pool_page-device-attribute.patch
documentation-document-zram-pages_per_pool_page-attribute.patch
zsmalloc-break-out-of-loop-when-found-perfect-zspage-order.patch
