| # SPDX-License-Identifier: GPL-2.0 |
| config ZRAM |
| tristate "Compressed RAM block device support" |
| depends on BLOCK && SYSFS && ZSMALLOC && CRYPTO |
| select CRYPTO_LZO |
| help |
| Creates virtual block devices called /dev/zramX (X = 0, 1, ...). |
| Pages written to these disks are compressed and stored in memory |
| itself. These disks allow very fast I/O and compression provides |
| good amounts of memory savings. |
| |
| It has several use cases, for example: /tmp storage, use as swap |
| disks and maybe many more. |
| |
| See Documentation/admin-guide/blockdev/zram.rst for more information. |
| |
| config ZRAM_WRITEBACK |
| bool "Write back incompressible or idle page to backing device" |
| depends on ZRAM |
| help |
| With incompressible page, there is no memory saving to keep it |
| in memory. Instead, write it out to backing device. |
| For this feature, admin should set up backing device via |
| /sys/block/zramX/backing_dev. |
| |
| With /sys/block/zramX/{idle,writeback}, application could ask |
| idle page's writeback to the backing device to save in memory. |
| |
| See Documentation/admin-guide/blockdev/zram.rst for more information. |
| |
| config ZRAM_MEMORY_TRACKING |
| bool "Track zRam block status" |
| depends on ZRAM && DEBUG_FS |
| help |
| With this feature, admin can track the state of allocated blocks |
| of zRAM. Admin could see the information via |
| /sys/kernel/debug/zram/zramX/block_state. |
| |
| See Documentation/admin-guide/blockdev/zram.rst for more information. |
