staging: zcache: fix typo "64_BIT"
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / staging / zcache / Kconfig
1 config ZCACHE
2 bool "Dynamic compression of swap pages and clean pagecache pages"
3 depends on CRYPTO=y && SWAP=y && CLEANCACHE && FRONTSWAP
4 select CRYPTO_LZO
5 default n
6 help
7 Zcache doubles RAM efficiency while providing a significant
8 performance boosts on many workloads. Zcache uses
9 compression and an in-kernel implementation of transcendent
10 memory to store clean page cache pages and swap in RAM,
11 providing a noticeable reduction in disk I/O.
12
13 config RAMSTER
14 bool "Cross-machine RAM capacity sharing, aka peer-to-peer tmem"
15 depends on CONFIGFS_FS=y && SYSFS=y && !HIGHMEM && ZCACHE=y
16 depends on NET
17 # must ensure struct page is 8-byte aligned
18 select HAVE_ALIGNED_STRUCT_PAGE if !64BIT
19 default n
20 help
21 RAMster allows RAM on other machines in a cluster to be utilized
22 dynamically and symmetrically instead of swapping to a local swap
23 disk, thus improving performance on memory-constrained workloads
24 while minimizing total RAM across the cluster. RAMster, like
25 zcache2, compresses swap pages into local RAM, but then remotifies
26 the compressed pages to another node in the RAMster cluster.
27
28 # Depends on not-yet-upstreamed mm patches to export end_swap_bio_write and
29 # __add_to_swap_cache, and implement __swap_writepage (which is swap_writepage
30 # without the frontswap call. When these are in-tree, the dependency on
31 # BROKEN can be removed
32 config ZCACHE_WRITEBACK
33 bool "Allow compressed swap pages to be writtenback to swap disk"
34 depends on ZCACHE=y && BROKEN
35 default n
36 help
37 Zcache caches compressed swap pages (and other data) in RAM which
38 often improves performance by avoiding I/O's due to swapping.
39 In some workloads with very long-lived large processes, it can
40 instead reduce performance. Writeback decompresses zcache-compressed
41 pages (in LRU order) when under memory pressure and writes them to
42 the backing swap disk to ameliorate this problem. Policy driving
43 writeback is still under development.