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9c3760eb80
We waste sizeof(swp_entry_t) for zswap header when using zsmalloc as zpool driver because zsmalloc doesn't support eviction. Add zpool_evictable() to detect if zpool is potentially evictable, and use it in zswap to avoid waste memory for zswap header. [yuzhao@google.com: The zpool->" prefix is a result of copy & paste] Link: http://lkml.kernel.org/r/20180110225626.110330-1-yuzhao@google.com Link: http://lkml.kernel.org/r/20180110224741.83751-1-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Dan Streetman <ddstreet@ieee.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
114 lines
3.0 KiB
C
114 lines
3.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* zpool memory storage api
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*
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* Copyright (C) 2014 Dan Streetman
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*
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* This is a common frontend for the zbud and zsmalloc memory
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* storage pool implementations. Typically, this is used to
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* store compressed memory.
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*/
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#ifndef _ZPOOL_H_
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#define _ZPOOL_H_
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struct zpool;
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struct zpool_ops {
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int (*evict)(struct zpool *pool, unsigned long handle);
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};
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/*
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* Control how a handle is mapped. It will be ignored if the
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* implementation does not support it. Its use is optional.
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* Note that this does not refer to memory protection, it
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* refers to how the memory will be copied in/out if copying
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* is necessary during mapping; read-write is the safest as
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* it copies the existing memory in on map, and copies the
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* changed memory back out on unmap. Write-only does not copy
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* in the memory and should only be used for initialization.
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* If in doubt, use ZPOOL_MM_DEFAULT which is read-write.
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*/
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enum zpool_mapmode {
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ZPOOL_MM_RW, /* normal read-write mapping */
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ZPOOL_MM_RO, /* read-only (no copy-out at unmap time) */
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ZPOOL_MM_WO, /* write-only (no copy-in at map time) */
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ZPOOL_MM_DEFAULT = ZPOOL_MM_RW
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};
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bool zpool_has_pool(char *type);
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struct zpool *zpool_create_pool(const char *type, const char *name,
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gfp_t gfp, const struct zpool_ops *ops);
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const char *zpool_get_type(struct zpool *pool);
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void zpool_destroy_pool(struct zpool *pool);
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int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
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unsigned long *handle);
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void zpool_free(struct zpool *pool, unsigned long handle);
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int zpool_shrink(struct zpool *pool, unsigned int pages,
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unsigned int *reclaimed);
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void *zpool_map_handle(struct zpool *pool, unsigned long handle,
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enum zpool_mapmode mm);
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void zpool_unmap_handle(struct zpool *pool, unsigned long handle);
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u64 zpool_get_total_size(struct zpool *pool);
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/**
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* struct zpool_driver - driver implementation for zpool
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* @type: name of the driver.
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* @list: entry in the list of zpool drivers.
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* @create: create a new pool.
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* @destroy: destroy a pool.
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* @malloc: allocate mem from a pool.
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* @free: free mem from a pool.
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* @shrink: shrink the pool.
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* @map: map a handle.
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* @unmap: unmap a handle.
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* @total_size: get total size of a pool.
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*
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* This is created by a zpool implementation and registered
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* with zpool.
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*/
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struct zpool_driver {
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char *type;
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struct module *owner;
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atomic_t refcount;
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struct list_head list;
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void *(*create)(const char *name,
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gfp_t gfp,
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const struct zpool_ops *ops,
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struct zpool *zpool);
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void (*destroy)(void *pool);
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int (*malloc)(void *pool, size_t size, gfp_t gfp,
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unsigned long *handle);
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void (*free)(void *pool, unsigned long handle);
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int (*shrink)(void *pool, unsigned int pages,
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unsigned int *reclaimed);
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void *(*map)(void *pool, unsigned long handle,
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enum zpool_mapmode mm);
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void (*unmap)(void *pool, unsigned long handle);
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u64 (*total_size)(void *pool);
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};
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void zpool_register_driver(struct zpool_driver *driver);
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int zpool_unregister_driver(struct zpool_driver *driver);
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bool zpool_evictable(struct zpool *pool);
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#endif
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