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68 lines
2.3 KiB
68 lines
2.3 KiB
# SPDX-License-Identifier: GPL-2.0
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config ZRAM
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tristate "Compressed RAM block device support"
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depends on BLOCK && SYSFS && ZSMALLOC && CRYPTO
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select CRYPTO_LZO
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default n
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help
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Creates virtual block devices called /dev/zramX (X = 0, 1, ...).
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Pages written to these disks are compressed and stored in memory
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itself. These disks allow very fast I/O and compression provides
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good amounts of memory savings.
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It has several use cases, for example: /tmp storage, use as swap
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disks and maybe many more.
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See Documentation/blockdev/zram.txt for more information.
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config ZRAM_DEDUP
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bool "Deduplication support for ZRAM data"
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depends on ZRAM
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select XXHASH
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default n
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help
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Deduplicate ZRAM data to reduce amount of memory consumption.
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Advantage largely depends on the workload. In some cases, this
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option reduces memory usage to the half. However, if there is no
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duplicated data, the amount of memory consumption would be
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increased due to additional metadata usage. And, there is
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computation time trade-off. Please check the benefit before
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enabling this option. Experiment shows the positive effect when
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the zram is used as blockdev and is used to store build output.
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config ZRAM_WRITEBACK
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bool "Write back incompressible or idle page to backing device"
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depends on ZRAM
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default n
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help
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With incompressible page, there is no memory saving to keep it
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in memory. Instead, write it out to backing device.
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For this feature, admin should set up backing device via
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/sys/block/zramX/backing_dev.
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With /sys/block/zramX/{idle,writeback}, application could ask
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idle page's writeback to the backing device to save in memory.
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See Documentation/blockdev/zram.txt for more information.
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config ZRAM_MEMORY_TRACKING
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bool "Track zRam block status"
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depends on ZRAM && DEBUG_FS
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help
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With this feature, admin can track the state of allocated blocks
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of zRAM. Admin could see the information via
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/sys/kernel/debug/zram/zramX/block_state.
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See Documentation/blockdev/zram.txt for more information.
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config ZRAM_LRU_WRITEBACK
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bool
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depends on ZRAM_WRITEBACK
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default n
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help
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This feature supports zram lru-based writeback (SQZR).
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config ZRAM_LRU_WRITEBACK_LIMIT
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int "Limit zram lru writeback"
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default 1024
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depends on ZRAM_LRU_WRITEBACK
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