drivers/staging/zram/xvmalloc_int.h

   1 /*
   2  * xvmalloc memory allocator
   3  *
   4  * Copyright (C) 2008, 2009, 2010  Nitin Gupta
   5  *
   6  * This code is released using a dual license strategy: BSD/GPL
   7  * You can choose the licence that better fits your requirements.
   8  *
   9  * Released under the terms of 3-clause BSD License
  10  * Released under the terms of GNU General Public License Version 2.0
  11  */
  12
  13 #ifndef _XV_MALLOC_INT_H_
  14 #define _XV_MALLOC_INT_H_
  15
  16 #include <linux/kernel.h>
  17 #include <linux/types.h>
  18
  19 /* User configurable params */
  20
  21 /* Must be power of two */
  22 #define XV_ALIGN_SHIFT  2
  23 #define XV_ALIGN        (1 << XV_ALIGN_SHIFT)
  24 #define XV_ALIGN_MASK   (XV_ALIGN - 1)
  25
  26 /* This must be greater than sizeof(link_free) */
  27 #define XV_MIN_ALLOC_SIZE       32
  28 #define XV_MAX_ALLOC_SIZE       (PAGE_SIZE - XV_ALIGN)
  29
  30 /* Free lists are separated by FL_DELTA bytes */
  31 #define FL_DELTA_SHIFT  3
  32 #define FL_DELTA        (1 << FL_DELTA_SHIFT)
  33 #define FL_DELTA_MASK   (FL_DELTA - 1)
  34 #define NUM_FREE_LISTS  ((XV_MAX_ALLOC_SIZE - XV_MIN_ALLOC_SIZE) \
  35                                 / FL_DELTA + 1)
  36
  37 #define MAX_FLI         DIV_ROUND_UP(NUM_FREE_LISTS, BITS_PER_LONG)
  38
  39 /* End of user params */
  40
  41 enum blockflags {
  42         BLOCK_FREE,
  43         PREV_FREE,
  44         __NR_BLOCKFLAGS,
  45 };
  46
  47 #define FLAGS_MASK      XV_ALIGN_MASK
  48 #define PREV_MASK       (~FLAGS_MASK)
  49
  50 struct freelist_entry {
  51         struct page *page;
  52         u16 offset;
  53         u16 pad;
  54 };
  55
  56 struct link_free {
  57         struct page *prev_page;
  58         struct page *next_page;
  59         u16 prev_offset;
  60         u16 next_offset;
  61 };
  62
  63 struct block_header {
  64         union {
  65                 /* This common header must be XV_ALIGN bytes */
  66                 u8 common[XV_ALIGN];
  67                 struct {
  68                         u16 size;
  69                         u16 prev;
  70                 };
  71         };
  72         struct link_free link;
  73 };
  74
  75 struct xv_pool {
  76         ulong flbitmap;
  77         ulong slbitmap[MAX_FLI];
  78         spinlock_t lock;
  79
  80         struct freelist_entry freelist[NUM_FREE_LISTS];
  81
  82         /* stats */
  83         u64 total_pages;
  84 };
  85
  86 #endif