01dabed205
If zram-generator package is installed and works, then we can not remove
zram module because zram swap is being used. This case needs a clean zram
environment, change this test by using hot_add/hot_remove interface. So
even zram device is being used, we still can add zram device and remove
them in cleanup.
The two interface was introduced since kernel commit 6566d1a32bf7("zram:
add dynamic device add/remove functionality") in v4.2-rc1. If kernel
supports these two interface, we use hot_add/hot_remove to slove this
problem, if not, just check whether zram is being used or built in, then
skip it on old kernel.
Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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|---|---|---|
| .. | ||
| config | ||
| Makefile | ||
| README | ||
| zram_lib.sh | ||
| zram.sh | ||
| zram01.sh | ||
| zram02.sh | ||
zram: Compressed RAM based block devices
- Introduction
The zram module creates RAM based block devices named /dev/zram ( = 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. Some of the usecases include /tmp storage, use as swap disks, various caches under /var and maybe many more :)
Statistics for individual zram devices are exported through sysfs nodes at /sys/block/zram/
Kconfig required: CONFIG_ZRAM=y CONFIG_CRYPTO_LZ4=y CONFIG_ZPOOL=y CONFIG_ZSMALLOC=y
ZRAM Testcases
zram_lib.sh: create library with initialization/cleanup functions zram.sh: For sanity check of CONFIG_ZRAM and to run zram01 and zram02
Two functional tests: zram01 and zram02: zram01.sh: creates general purpose ram disks with ext4 filesystems zram02.sh: creates block device for swap
Commands required for testing:
- bc
- dd
- free
- awk
- mkswap
- swapon
- swapoff
- mkfs/ mkfs.ext4
For more information please refer: kernel-source-tree/Documentation/admin-guide/blockdev/zram.rst