mm/percpu-internal.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _MM_PERCPU_INTERNAL_H
   3 #define _MM_PERCPU_INTERNAL_H
   4
   5 #include <linux/types.h>
   6 #include <linux/percpu.h>
   7
   8 /*
   9  * pcpu_block_md is the metadata block struct.
  10  * Each chunk's bitmap is split into a number of full blocks.
  11  * All units are in terms of bits.
  12  *
  13  * The scan hint is the largest known contiguous area before the contig hint.
  14  * It is not necessarily the actual largest contig hint though.  There is an
  15  * invariant that the scan_hint_start > contig_hint_start iff
  16  * scan_hint == contig_hint.  This is necessary because when scanning forward,
  17  * we don't know if a new contig hint would be better than the current one.
  18  */
  19 struct pcpu_block_md {
  20         int                     scan_hint;      /* scan hint for block */
  21         int                     scan_hint_start; /* block relative starting
  22                                                     position of the scan hint */
  23         int                     contig_hint;    /* contig hint for block */
  24         int                     contig_hint_start; /* block relative starting
  25                                                       position of the contig hint */
  26         int                     left_free;      /* size of free space along
  27                                                    the left side of the block */
  28         int                     right_free;     /* size of free space along
  29                                                    the right side of the block */
  30         int                     first_free;     /* block position of first free */
  31         int                     nr_bits;        /* total bits responsible for */
  32 };
  33
  34 struct pcpu_chunk {
  35 #ifdef CONFIG_PERCPU_STATS
  36         int                     nr_alloc;       /* # of allocations */
  37         size_t                  max_alloc_size; /* largest allocation size */
  38 #endif
  39
  40         struct list_head        list;           /* linked to pcpu_slot lists */
  41         int                     free_bytes;     /* free bytes in the chunk */
  42         struct pcpu_block_md    chunk_md;
  43         void                    *base_addr;     /* base address of this chunk */
  44
  45         unsigned long           *alloc_map;     /* allocation map */
  46         unsigned long           *bound_map;     /* boundary map */
  47         struct pcpu_block_md    *md_blocks;     /* metadata blocks */
  48
  49         void                    *data;          /* chunk data */
  50         bool                    immutable;      /* no [de]population allowed */
  51         int                     start_offset;   /* the overlap with the previous
  52                                                    region to have a page aligned
  53                                                    base_addr */
  54         int                     end_offset;     /* additional area required to
  55                                                    have the region end page
  56                                                    aligned */
  57
  58         int                     nr_pages;       /* # of pages served by this chunk */
  59         int                     nr_populated;   /* # of populated pages */
  60         int                     nr_empty_pop_pages; /* # of empty populated pages */
  61         unsigned long           populated[];    /* populated bitmap */
  62 };
  63
  64 extern spinlock_t pcpu_lock;
  65
  66 extern struct list_head *pcpu_slot;
  67 extern int pcpu_nr_slots;
  68 extern int pcpu_nr_empty_pop_pages;
  69
  70 extern struct pcpu_chunk *pcpu_first_chunk;
  71 extern struct pcpu_chunk *pcpu_reserved_chunk;
  72
  73 /**
  74  * pcpu_chunk_nr_blocks - converts nr_pages to # of md_blocks
  75  * @chunk: chunk of interest
  76  *
  77  * This conversion is from the number of physical pages that the chunk
  78  * serves to the number of bitmap blocks used.
  79  */
  80 static inline int pcpu_chunk_nr_blocks(struct pcpu_chunk *chunk)
  81 {
  82         return chunk->nr_pages * PAGE_SIZE / PCPU_BITMAP_BLOCK_SIZE;
  83 }
  84
  85 /**
  86  * pcpu_nr_pages_to_map_bits - converts the pages to size of bitmap
  87  * @pages: number of physical pages
  88  *
  89  * This conversion is from physical pages to the number of bits
  90  * required in the bitmap.
  91  */
  92 static inline int pcpu_nr_pages_to_map_bits(int pages)
  93 {
  94         return pages * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE;
  95 }
  96
  97 /**
  98  * pcpu_chunk_map_bits - helper to convert nr_pages to size of bitmap
  99  * @chunk: chunk of interest
 100  *
 101  * This conversion is from the number of physical pages that the chunk
 102  * serves to the number of bits in the bitmap.
 103  */
 104 static inline int pcpu_chunk_map_bits(struct pcpu_chunk *chunk)
 105 {
 106         return pcpu_nr_pages_to_map_bits(chunk->nr_pages);
 107 }
 108
 109 #ifdef CONFIG_PERCPU_STATS
 110
 111 #include <linux/spinlock.h>
 112
 113 struct percpu_stats {
 114         u64 nr_alloc;           /* lifetime # of allocations */
 115         u64 nr_dealloc;         /* lifetime # of deallocations */
 116         u64 nr_cur_alloc;       /* current # of allocations */
 117         u64 nr_max_alloc;       /* max # of live allocations */
 118         u32 nr_chunks;          /* current # of live chunks */
 119         u32 nr_max_chunks;      /* max # of live chunks */
 120         size_t min_alloc_size;  /* min allocaiton size */
 121         size_t max_alloc_size;  /* max allocation size */
 122 };
 123
 124 extern struct percpu_stats pcpu_stats;
 125 extern struct pcpu_alloc_info pcpu_stats_ai;
 126
 127 /*
 128  * For debug purposes. We don't care about the flexible array.
 129  */
 130 static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
 131 {
 132         memcpy(&pcpu_stats_ai, ai, sizeof(struct pcpu_alloc_info));
 133
 134         /* initialize min_alloc_size to unit_size */
 135         pcpu_stats.min_alloc_size = pcpu_stats_ai.unit_size;
 136 }
 137
 138 /*
 139  * pcpu_stats_area_alloc - increment area allocation stats
 140  * @chunk: the location of the area being allocated
 141  * @size: size of area to allocate in bytes
 142  *
 143  * CONTEXT:
 144  * pcpu_lock.
 145  */
 146 static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
 147 {
 148         lockdep_assert_held(&pcpu_lock);
 149
 150         pcpu_stats.nr_alloc++;
 151         pcpu_stats.nr_cur_alloc++;
 152         pcpu_stats.nr_max_alloc =
 153                 max(pcpu_stats.nr_max_alloc, pcpu_stats.nr_cur_alloc);
 154         pcpu_stats.min_alloc_size =
 155                 min(pcpu_stats.min_alloc_size, size);
 156         pcpu_stats.max_alloc_size =
 157                 max(pcpu_stats.max_alloc_size, size);
 158
 159         chunk->nr_alloc++;
 160         chunk->max_alloc_size = max(chunk->max_alloc_size, size);
 161 }
 162
 163 /*
 164  * pcpu_stats_area_dealloc - decrement allocation stats
 165  * @chunk: the location of the area being deallocated
 166  *
 167  * CONTEXT:
 168  * pcpu_lock.
 169  */
 170 static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
 171 {
 172         lockdep_assert_held(&pcpu_lock);
 173
 174         pcpu_stats.nr_dealloc++;
 175         pcpu_stats.nr_cur_alloc--;
 176
 177         chunk->nr_alloc--;
 178 }
 179
 180 /*
 181  * pcpu_stats_chunk_alloc - increment chunk stats
 182  */
 183 static inline void pcpu_stats_chunk_alloc(void)
 184 {
 185         unsigned long flags;
 186         spin_lock_irqsave(&pcpu_lock, flags);
 187
 188         pcpu_stats.nr_chunks++;
 189         pcpu_stats.nr_max_chunks =
 190                 max(pcpu_stats.nr_max_chunks, pcpu_stats.nr_chunks);
 191
 192         spin_unlock_irqrestore(&pcpu_lock, flags);
 193 }
 194
 195 /*
 196  * pcpu_stats_chunk_dealloc - decrement chunk stats
 197  */
 198 static inline void pcpu_stats_chunk_dealloc(void)
 199 {
 200         unsigned long flags;
 201         spin_lock_irqsave(&pcpu_lock, flags);
 202
 203         pcpu_stats.nr_chunks--;
 204
 205         spin_unlock_irqrestore(&pcpu_lock, flags);
 206 }
 207
 208 #else
 209
 210 static inline void pcpu_stats_save_ai(const struct pcpu_alloc_info *ai)
 211 {
 212 }
 213
 214 static inline void pcpu_stats_area_alloc(struct pcpu_chunk *chunk, size_t size)
 215 {
 216 }
 217
 218 static inline void pcpu_stats_area_dealloc(struct pcpu_chunk *chunk)
 219 {
 220 }
 221
 222 static inline void pcpu_stats_chunk_alloc(void)
 223 {
 224 }
 225
 226 static inline void pcpu_stats_chunk_dealloc(void)
 227 {
 228 }
 229
 230 #endif /* !CONFIG_PERCPU_STATS */
 231
 232 #endif