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| author |   Minchan Kim <minchan@kernel.org> | 2018-12-28 00:36:44 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 12:11:49 -0800 |
| commit | e82592c4fd7eafe8dec12a70436e93e3afb28556 (patch) | |
| tree | 89d470bbfcb0f97e7f3ed3f1516d038403992078 /Documentation | |
| parent | zram: refactor flags and writeback stuff (diff) | |
| download | linux-dev-e82592c4fd7eafe8dec12a70436e93e3afb28556.tar.xz linux-dev-e82592c4fd7eafe8dec12a70436e93e3afb28556.zip | |
zram: introduce ZRAM_IDLE flag
To support idle page writeback with upcoming patches, this patch
introduces a new ZRAM_IDLE flag.
Userspace can mark zram slots as "idle" via
"echo all > /sys/block/zramX/idle"
which marks every allocated zram slot as ZRAM_IDLE.
User could see it by /sys/kernel/debug/zram/zram0/block_state.
300 75.033841 ...i
301 63.806904 s..i
302 63.806919 ..hi
Once there is IO for the slot, the mark will be disappeared.
300 75.033841 ...
301 63.806904 s..i
302 63.806919 ..hi
Therefore, 300th block is idle zpage. With this feature,
user can how many zram has idle pages which are waste of memory.
Link: http://lkml.kernel.org/r/20181127055429.251614-5-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Joey Pabalinas <joeypabalinas@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 | 10 |
2 files changed, 14 insertions, 4 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram index c1513c756af1..04c9a5980bc7 100644 --- a/Documentation/ABI/testing/sysfs-block-zram +++ b/Documentation/ABI/testing/sysfs-block-zram @@ -98,3 +98,11 @@ 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. + +What: /sys/block/zram<id>/idle +Date: November 2018 +Contact: Minchan Kim <minchan@kernel.org> +Description: + idle file is write-only and mark zram slot as idle. + If system has mounted debugfs, user can see which slots + are idle via /sys/kernel/debug/zram/zram<id>/block_state diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 3c1b5ab54bc0..f3bcd716d8a9 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -169,6 +169,7 @@ 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 +idle WO mark allocated slot as idle User space is advised to use the following files to read the device statistics. @@ -251,16 +252,17 @@ pages of the process with*pagemap. If you enable the feature, you could see block state via /sys/kernel/debug/zram/zram0/block_state". The output is as follows, - 300 75.033841 .wh - 301 63.806904 s.. - 302 63.806919 ..h + 300 75.033841 .wh. + 301 63.806904 s... + 302 63.806919 ..hi First column is zram's block index. Second column is access time since the system was booted Third column is state of the block. (s: same page w: written page to backing store -h: huge page) +h: huge page +i: idle page) First line of above example says 300th block is accessed at 75.033841sec and the block's state is huge so it is written back to the backing |