diff options
| author | Sergey Senozhatsky <senozhatsky@chromium.org> | 2025-12-01 18:47:50 +0900 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-01-20 19:24:36 -0800 |
| commit | 2502673aed6c66befc7efc2dc008e2a8a50508cd (patch) | |
| tree | 4ffe67fdf0e1c8332ef3e830933022a13840f08b | |
| parent | 4c1d61389e8e4307449eb2ebad997241cbf08fef (diff) | |
zram: document writeback_batch_size
Add missing writeback_batch_size documentation.
Link: https://lkml.kernel.org/r/20251201094754.4149975-4-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block-zram | 7 | ||||
| -rw-r--r-- | Documentation/admin-guide/blockdev/zram.rst | 11 |
2 files changed, 17 insertions, 1 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram index ed10c2e4b5c2..e538d4850d61 100644 --- a/Documentation/ABI/testing/sysfs-block-zram +++ b/Documentation/ABI/testing/sysfs-block-zram @@ -157,3 +157,10 @@ Contact: Richard Chang <richardycc@google.com> Description: The writeback_compressed device atrribute toggles compressed writeback feature. + +What: /sys/block/zram<id>/writeback_batch_size +Date: November 2025 +Contact: Sergey Senozhatsky <senozhatsky@chromium.org> +Description: + The writeback_batch_size device atrribute sets the maximum + number of in-flight writeback operations. diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst index 9547e4e95979..94bb7f2245ee 100644 --- a/Documentation/admin-guide/blockdev/zram.rst +++ b/Documentation/admin-guide/blockdev/zram.rst @@ -214,6 +214,8 @@ mem_limit WO specifies the maximum amount of memory ZRAM can writeback_limit WO specifies the maximum amount of write IO zram can write out to backing device as 4KB unit writeback_limit_enable RW show and set writeback_limit feature +writeback_batch_size RW show and set maximum number of in-flight + writeback operations writeback_compressed RW show and set compressed writeback feature comp_algorithm RW show and change the compression algorithm algorithm_params WO setup compression algorithm parameters @@ -223,7 +225,6 @@ backing_dev RW set up backend storage for zram to write out idle WO mark allocated slot as idle ====================== ====== =============================================== - User space is advised to use the following files to read the device statistics. File /sys/block/zram<id>/stat @@ -447,6 +448,14 @@ this feature, execute:: Note that this feature should be configured before the `zramX` device is initialized. +Depending on backing device storage type, writeback operation may benefit +from a higher number of in-flight write requests (batched writes). The +number of maximum in-flight writeback operations can be configured via +`writeback_batch_size` attribute. To change the default value (which is 32), +execute:: + + $ echo 64 > /sys/block/zramX/writeback_batch_size + If admin wants to measure writeback count in a certain period, they could know it via /sys/block/zram0/bd_stat's 3rd column. |