From e82592c4fd7eafe8dec12a70436e93e3afb28556 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Fri, 28 Dec 2018 00:36:44 -0800 Subject: 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 Reviewed-by: Sergey Senozhatsky Reviewed-by: Joey Pabalinas Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/ABI/testing/sysfs-block-zram | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation/ABI/testing') 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/idle +Date: November 2018 +Contact: Minchan Kim +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/block_state -- cgit v1.2.3