Provide a simple documentation for zram pool_page_order device attribute. Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> --- Documentation/admin-guide/blockdev/zram.rst | 31 ++++++++++++++++----- 1 file changed, 24 insertions(+), 7 deletions(-) diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst index 010fb05a5999..cd12a5982ae0 100644 --- a/Documentation/admin-guide/blockdev/zram.rst +++ b/Documentation/admin-guide/blockdev/zram.rst @@ -112,7 +112,24 @@ to list all of them using, for instance, /proc/crypto or any other 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 maximum pool page order +============================== + +zsmalloc pages can consist of up to 2^N physical pages. The exact size +is calculated per each zsmalloc size class during zsmalloc pool creation. +ZRAM provides pool_page_order device attribute to see or change N. + +Examples:: + + #show current maximum zsmalloc page order + cat /sys/block/zramX/pool_page_order + 2 + + #set maximum zsmalloc page order + echo 3 > /sys/block/zramX/pool_page_order + + +5) Set Disksize =============== Set disk size by writing the value to sysfs node 'disksize'. @@ -132,7 +149,7 @@ There is little point creating a zram of greater than twice the size of memory 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 +168,7 @@ Examples:: # To disable memory limit echo 0 > /sys/block/zram0/mem_limit -6) Activate +7) Activate =========== :: @@ -162,7 +179,7 @@ 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 +199,7 @@ 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>/ @@ -283,7 +300,7 @@ a single line of text and contains the following stats separated by whitespace: Unit: 4K bytes ============== ============================================================= -9) Deactivate +10) Deactivate ============= :: @@ -291,7 +308,7 @@ a single line of text and contains the following stats separated by whitespace: swapoff /dev/zram0 umount /dev/zram1 -10) Reset +11) Reset ========= Write any positive value to 'reset' sysfs node:: -- 2.38.0.135.g90850a2211-goog
