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Diffstat (limited to 'Documentation/blockdev/zram.txt')
| -rw-r--r-- | Documentation/blockdev/zram.txt | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index f3bcd716d8a9..806cdaabac83 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -238,11 +238,31 @@ line of text and contains the following stats separated by whitespace: = writeback -With incompressible pages, there is no memory saving with zram. -Instead, with CONFIG_ZRAM_WRITEBACK, zram can write incompressible page +With CONFIG_ZRAM_WRITEBACK, zram can write idle/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. +To use the feature, admin should set up backing device via + + "echo /dev/sda5 > /sys/block/zramX/backing_dev" + +before disksize setting. It supports only partition at this moment. +If admin want to use incompressible page writeback, they could do via + + "echo huge > /sys/block/zramX/write" + +To use idle page writeback, first, user need to declare zram pages +as idle. + + "echo all > /sys/block/zramX/idle" + +From now on, any pages on zram are idle pages. The idle mark +will be removed until someone request access of the block. +IOW, unless there is access request, those pages are still idle pages. + +Admin can request writeback of those idle pages at right timing via + + "echo idle > /sys/block/zramX/writeback" + +With the command, zram writeback idle pages from memory to the storage. = memory tracking |