projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| d651b886 | 1 | config ZCACHE |
| faca2ef7 | 2 | bool "Dynamic compression of swap pages and clean pagecache pages" |
| d651b886 | 3 | depends on CRYPTO=y && SWAP=y && CLEANCACHE && FRONTSWAP |
| faca2ef7 DM |
4 | select CRYPTO_LZO |
| 5 | default n | |
| 6 | help | |
| d651b886 DM |
7 | Zcache doubles RAM efficiency while providing a significant |
| 8 | performance boosts on many workloads. Zcache uses | |
| faca2ef7 DM |
9 | compression and an in-kernel implementation of transcendent |
| 10 | memory to store clean page cache pages and swap in RAM, | |
| d651b886 | 11 | providing a noticeable reduction in disk I/O. |
| 14c9fda5 | 12 | |
| 67e2cba4 KRW |
13 | config ZCACHE_DEBUG |
| 14 | bool "Enable debug statistics" | |
| 15 | depends on DEBUG_FS && ZCACHE | |
| 16 | default n | |
| 17 | help | |
| 18 | This is used to provide an debugfs directory with counters of | |
| 19 | how zcache is doing. You probably want to set this to 'N'. | |
| 20 | ||
| 14c9fda5 DM |
21 | config RAMSTER |
| 22 | bool "Cross-machine RAM capacity sharing, aka peer-to-peer tmem" | |
| d651b886 | 23 | depends on CONFIGFS_FS=y && SYSFS=y && !HIGHMEM && ZCACHE=y |
| b3ca610a | 24 | depends on NET |
| 14c9fda5 | 25 | # must ensure struct page is 8-byte aligned |
| 27ca0391 | 26 | select HAVE_ALIGNED_STRUCT_PAGE if !64BIT |
| 14c9fda5 DM |
27 | default n |
| 28 | help | |
| 29 | RAMster allows RAM on other machines in a cluster to be utilized | |
| 30 | dynamically and symmetrically instead of swapping to a local swap | |
| 31 | disk, thus improving performance on memory-constrained workloads | |
| 32 | while minimizing total RAM across the cluster. RAMster, like | |
| 33 | zcache2, compresses swap pages into local RAM, but then remotifies | |
| 34 | the compressed pages to another node in the RAMster cluster. | |
| 76426daf DM |
35 | |
| 36 | # Depends on not-yet-upstreamed mm patches to export end_swap_bio_write and | |
| 37 | # __add_to_swap_cache, and implement __swap_writepage (which is swap_writepage | |
| 38 | # without the frontswap call. When these are in-tree, the dependency on | |
| 39 | # BROKEN can be removed | |
| 40 | config ZCACHE_WRITEBACK | |
| 41 | bool "Allow compressed swap pages to be writtenback to swap disk" | |
| 42 | depends on ZCACHE=y && BROKEN | |
| 43 | default n | |
| 44 | help | |
| 45 | Zcache caches compressed swap pages (and other data) in RAM which | |
| 46 | often improves performance by avoiding I/O's due to swapping. | |
| 47 | In some workloads with very long-lived large processes, it can | |
| 48 | instead reduce performance. Writeback decompresses zcache-compressed | |
| 49 | pages (in LRU order) when under memory pressure and writes them to | |
| 50 | the backing swap disk to ameliorate this problem. Policy driving | |
| 51 | writeback is still under development. |