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| author | Minchan Kim <minchan@kernel.org> | 2017-09-07 01:20:10 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-07 02:27:25 +0200 |
| commit | 5a47074f0279421778f97b1b1e75686696a5f42a (patch) | |
| tree | fd81ff3aaa8a707428ba2daadb66fc2c6b28c297 /Documentation | |
| parent | zram: read page from backing device (diff) | |
| download | linux-5a47074f0279421778f97b1b1e75686696a5f42a.tar.xz linux-5a47074f0279421778f97b1b1e75686696a5f42a.zip | |
zram: add config and doc file for writeback feature
This patch adds document and kconfig for using of writeback feature.
Link: http://lkml.kernel.org/r/1498459987-24562-10-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Juneho Choi <juno.choi@lge.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block-zram | 8 | ||||
| -rw-r--r-- | Documentation/blockdev/zram.txt | 11 |
2 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram index 451b6d882b2c..c1513c756af1 100644 --- a/Documentation/ABI/testing/sysfs-block-zram +++ b/Documentation/ABI/testing/sysfs-block-zram @@ -90,3 +90,11 @@ Description: device's debugging info useful for kernel developers. Its format is not documented intentionally and may change anytime without any notice. + +What: /sys/block/zram<id>/backing_dev +Date: June 2017 +Contact: Minchan Kim <minchan@kernel.org> +Description: + The backing_dev file is read-write and set up backing + device for zram to write incompressible pages. + For using, user should enable CONFIG_ZRAM_WRITEBACK. diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 4fced8a21307..257e65714c6a 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -168,6 +168,7 @@ max_comp_streams RW the number of possible concurrent compress operations comp_algorithm RW show and change the compression algorithm compact WO trigger memory compaction debug_stat RO this file is used for zram debugging purposes +backing_dev RW set up backend storage for zram to write out User space is advised to use the following files to read the device statistics. @@ -231,5 +232,15 @@ line of text and contains the following stats separated by whitespace: resets the disksize to zero. You must set the disksize again before reusing the device. +* Optional Feature + += writeback + +With incompressible pages, there is no memory saving with zram. +Instead, with CONFIG_ZRAM_WRITEBACK, zram can write incompressible page +to backing storage rather than keeping it in memory. +User should set up backing device via /sys/block/zramX/backing_dev +before disksize setting. + Nitin Gupta ngupta@vflare.org |