linux_old1/include/linux/zsmalloc.h

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/*
* zsmalloc memory allocator
*
* Copyright (C) 2011 Nitin Gupta
* Copyright (C) 2012, 2013 Minchan Kim
*
* This code is released using a dual license strategy: BSD/GPL
* You can choose the license that better fits your requirements.
*
* Released under the terms of 3-clause BSD License
* Released under the terms of GNU General Public License Version 2.0
*/
#ifndef _ZS_MALLOC_H_
#define _ZS_MALLOC_H_
#include <linux/types.h>
/*
* zsmalloc mapping modes
*
* NOTE: These only make a difference when a mapped object spans pages.
* They also have no effect when PGTABLE_MAPPING is selected.
*/
enum zs_mapmode {
ZS_MM_RW, /* normal read-write mapping */
ZS_MM_RO, /* read-only (no copy-out at unmap time) */
ZS_MM_WO /* write-only (no copy-in at map time) */
/*
* NOTE: ZS_MM_WO should only be used for initializing new
* (uninitialized) allocations. Partial writes to already
* initialized allocations should use ZS_MM_RW to preserve the
* existing data.
*/
};
struct zs_pool_stats {
/* How many pages were migrated (freed) */
unsigned long pages_compacted;
};
struct zs_pool;
struct zs_pool *zs_create_pool(const char *name, gfp_t flags);
void zs_destroy_pool(struct zs_pool *pool);
unsigned long zs_malloc(struct zs_pool *pool, size_t size);
void zs_free(struct zs_pool *pool, unsigned long obj);
void *zs_map_object(struct zs_pool *pool, unsigned long handle,
enum zs_mapmode mm);
void zs_unmap_object(struct zs_pool *pool, unsigned long handle);
unsigned long zs_get_total_pages(struct zs_pool *pool);
zsmalloc: support compaction This patch provides core functions for migration of zsmalloc. Migraion policy is simple as follows. for each size class { while { src_page = get zs_page from ZS_ALMOST_EMPTY if (!src_page) break; dst_page = get zs_page from ZS_ALMOST_FULL if (!dst_page) dst_page = get zs_page from ZS_ALMOST_EMPTY if (!dst_page) break; migrate(from src_page, to dst_page); } } For migration, we need to identify which objects in zspage are allocated to migrate them out. We could know it by iterating of freed objects in a zspage because first_page of zspage keeps free objects singly-linked list but it's not efficient. Instead, this patch adds a tag(ie, OBJ_ALLOCATED_TAG) in header of each object(ie, handle) so we could check whether the object is allocated easily. This patch adds another status bit in handle to synchronize between user access through zs_map_object and migration. During migration, we cannot move objects user are using due to data coherency between old object and new object. [akpm@linux-foundation.org: zsmalloc.c needs sched.h for cond_resched()] Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Juneho Choi <juno.choi@lge.com> Cc: Gunho Lee <gunho.lee@lge.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-16 07:15:30 +08:00
unsigned long zs_compact(struct zs_pool *pool);
void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats);
#endif