From af8d417a04564bca0348e7e3c749ab12a3e837ad Mon Sep 17 00:00:00 2001 From: Dan Streetman Date: Wed, 6 Aug 2014 16:08:36 -0700 Subject: mm/zpool: implement common zpool api to zbud/zsmalloc Add zpool api. zpool provides an interface for memory storage, typically of compressed memory. Users can select what backend to use; currently the only implementations are zbud, a low density implementation with up to two compressed pages per storage page, and zsmalloc, a higher density implementation with multiple compressed pages per storage page. Signed-off-by: Dan Streetman Tested-by: Seth Jennings Cc: Minchan Kim Cc: Nitin Gupta Cc: Weijie Yang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/zpool.h | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 include/linux/zpool.h (limited to 'include') diff --git a/include/linux/zpool.h b/include/linux/zpool.h new file mode 100644 index 000000000000..f14bd75f08b3 --- /dev/null +++ b/include/linux/zpool.h @@ -0,0 +1,106 @@ +/* + * zpool memory storage api + * + * Copyright (C) 2014 Dan Streetman + * + * This is a common frontend for the zbud and zsmalloc memory + * storage pool implementations. Typically, this is used to + * store compressed memory. + */ + +#ifndef _ZPOOL_H_ +#define _ZPOOL_H_ + +struct zpool; + +struct zpool_ops { + int (*evict)(struct zpool *pool, unsigned long handle); +}; + +/* + * Control how a handle is mapped. It will be ignored if the + * implementation does not support it. Its use is optional. + * Note that this does not refer to memory protection, it + * refers to how the memory will be copied in/out if copying + * is necessary during mapping; read-write is the safest as + * it copies the existing memory in on map, and copies the + * changed memory back out on unmap. Write-only does not copy + * in the memory and should only be used for initialization. + * If in doubt, use ZPOOL_MM_DEFAULT which is read-write. + */ +enum zpool_mapmode { + ZPOOL_MM_RW, /* normal read-write mapping */ + ZPOOL_MM_RO, /* read-only (no copy-out at unmap time) */ + ZPOOL_MM_WO, /* write-only (no copy-in at map time) */ + + ZPOOL_MM_DEFAULT = ZPOOL_MM_RW +}; + +struct zpool *zpool_create_pool(char *type, gfp_t gfp, struct zpool_ops *ops); + +char *zpool_get_type(struct zpool *pool); + +void zpool_destroy_pool(struct zpool *pool); + +int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp, + unsigned long *handle); + +void zpool_free(struct zpool *pool, unsigned long handle); + +int zpool_shrink(struct zpool *pool, unsigned int pages, + unsigned int *reclaimed); + +void *zpool_map_handle(struct zpool *pool, unsigned long handle, + enum zpool_mapmode mm); + +void zpool_unmap_handle(struct zpool *pool, unsigned long handle); + +u64 zpool_get_total_size(struct zpool *pool); + + +/** + * struct zpool_driver - driver implementation for zpool + * @type: name of the driver. + * @list: entry in the list of zpool drivers. + * @create: create a new pool. + * @destroy: destroy a pool. + * @malloc: allocate mem from a pool. + * @free: free mem from a pool. + * @shrink: shrink the pool. + * @map: map a handle. + * @unmap: unmap a handle. + * @total_size: get total size of a pool. + * + * This is created by a zpool implementation and registered + * with zpool. + */ +struct zpool_driver { + char *type; + struct module *owner; + atomic_t refcount; + struct list_head list; + + void *(*create)(gfp_t gfp, struct zpool_ops *ops); + void (*destroy)(void *pool); + + int (*malloc)(void *pool, size_t size, gfp_t gfp, + unsigned long *handle); + void (*free)(void *pool, unsigned long handle); + + int (*shrink)(void *pool, unsigned int pages, + unsigned int *reclaimed); + + void *(*map)(void *pool, unsigned long handle, + enum zpool_mapmode mm); + void (*unmap)(void *pool, unsigned long handle); + + u64 (*total_size)(void *pool); +}; + +void zpool_register_driver(struct zpool_driver *driver); + +int zpool_unregister_driver(struct zpool_driver *driver); + +int zpool_evict(void *pool, unsigned long handle); + +#endif -- cgit v1.2.3-58-ga151