src/gallium/auxiliary/pipebuffer/pb_cache.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007-2008 VMware, Inc.
   4  * Copyright 2015 Advanced Micro Devices, Inc.
   5  * All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the
   9  * "Software"), to deal in the Software without restriction, including
  10  * without limitation the rights to use, copy, modify, merge, publish,
  11  * distribute, sub license, and/or sell copies of the Software, and to
  12  * permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice (including the
  16  * next paragraph) shall be included in all copies or substantial portions
  17  * of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  21  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  22  * IN NO EVENT SHALL AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
  23  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  24  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  25  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  26  *
  27  **************************************************************************/
  28
  29 #include "pb_cache.h"
  30 #include "util/u_memory.h"
  31 #include "util/u_time.h"
  32
  33
  34 /**
  35  * Actually destroy the buffer.
  36  */
  37 static void
  38 destroy_buffer_locked(struct pb_cache_entry *entry)
  39 {
  40    struct pb_cache *mgr = entry->mgr;
  41
  42    assert(!pipe_is_referenced(&entry->buffer->reference));
  43    if (entry->head.next) {
  44       LIST_DEL(&entry->head);
  45       assert(mgr->num_buffers);
  46       --mgr->num_buffers;
  47       mgr->cache_size -= entry->buffer->size;
  48    }
  49    entry->mgr->destroy_buffer(entry->buffer);
  50 }
  51
  52 /**
  53  * Free as many cache buffers from the list head as possible.
  54  */
  55 static void
  56 release_expired_buffers_locked(struct list_head *cache)
  57 {
  58    struct list_head *curr, *next;
  59    struct pb_cache_entry *entry;
  60    int64_t now;
  61
  62    now = os_time_get();
  63
  64    curr = cache->next;
  65    next = curr->next;
  66    while (curr != cache) {
  67       entry = LIST_ENTRY(struct pb_cache_entry, curr, head);
  68
  69       if (!os_time_timeout(entry->start, entry->end, now))
  70          break;
  71
  72       destroy_buffer_locked(entry);
  73
  74       curr = next;
  75       next = curr->next;
  76    }
  77 }
  78
  79 /**
  80  * Add a buffer to the cache. This is typically done when the buffer is
  81  * being released.
  82  */
  83 void
  84 pb_cache_add_buffer(struct pb_cache_entry *entry)
  85 {
  86    struct pb_cache *mgr = entry->mgr;
  87    struct list_head *cache = &mgr->buckets[entry->bucket_index];
  88    unsigned i;
  89
  90    pipe_mutex_lock(mgr->mutex);
  91    assert(!pipe_is_referenced(&entry->buffer->reference));
  92
  93    for (i = 0; i < ARRAY_SIZE(mgr->buckets); i++)
  94       release_expired_buffers_locked(&mgr->buckets[i]);
  95
  96    /* Directly release any buffer that exceeds the limit. */
  97    if (mgr->cache_size + entry->buffer->size > mgr->max_cache_size) {
  98       entry->mgr->destroy_buffer(entry->buffer);
  99       pipe_mutex_unlock(mgr->mutex);
 100       return;
 101    }
 102
 103    entry->start = os_time_get();
 104    entry->end = entry->start + mgr->usecs;
 105    LIST_ADDTAIL(&entry->head, cache);
 106    ++mgr->num_buffers;
 107    mgr->cache_size += entry->buffer->size;
 108    pipe_mutex_unlock(mgr->mutex);
 109 }
 110
 111 /**
 112  * \return 1   if compatible and can be reclaimed
 113  *         0   if incompatible
 114  *        -1   if compatible and can't be reclaimed
 115  */
 116 static int
 117 pb_cache_is_buffer_compat(struct pb_cache_entry *entry,
 118                           pb_size size, unsigned alignment, unsigned usage)
 119 {
 120    struct pb_cache *mgr = entry->mgr;
 121    struct pb_buffer *buf = entry->buffer;
 122
 123    if (!pb_check_usage(usage, buf->usage))
 124       return 0;
 125
 126    /* be lenient with size */
 127    if (buf->size < size ||
 128        buf->size > (unsigned) (mgr->size_factor * size))
 129       return 0;
 130
 131    if (usage & mgr->bypass_usage)
 132       return 0;
 133
 134    if (!pb_check_alignment(alignment, buf->alignment))
 135       return 0;
 136
 137    return mgr->can_reclaim(buf) ? 1 : -1;
 138 }
 139
 140 /**
 141  * Find a compatible buffer in the cache, return it, and remove it
 142  * from the cache.
 143  */
 144 struct pb_buffer *
 145 pb_cache_reclaim_buffer(struct pb_cache *mgr, pb_size size,
 146                         unsigned alignment, unsigned usage,
 147                         unsigned bucket_index)
 148 {
 149    struct pb_cache_entry *entry;
 150    struct pb_cache_entry *cur_entry;
 151    struct list_head *cur, *next;
 152    int64_t now;
 153    int ret = 0;
 154    struct list_head *cache = &mgr->buckets[bucket_index];
 155
 156    pipe_mutex_lock(mgr->mutex);
 157
 158    entry = NULL;
 159    cur = cache->next;
 160    next = cur->next;
 161
 162    /* search in the expired buffers, freeing them in the process */
 163    now = os_time_get();
 164    while (cur != cache) {
 165       cur_entry = LIST_ENTRY(struct pb_cache_entry, cur, head);
 166
 167       if (!entry && (ret = pb_cache_is_buffer_compat(cur_entry, size,
 168                                                      alignment, usage) > 0))
 169          entry = cur_entry;
 170       else if (os_time_timeout(cur_entry->start, cur_entry->end, now))
 171          destroy_buffer_locked(cur_entry);
 172       else
 173          /* This buffer (and all hereafter) are still hot in cache */
 174          break;
 175
 176       /* the buffer is busy (and probably all remaining ones too) */
 177       if (ret == -1)
 178          break;
 179
 180       cur = next;
 181       next = cur->next;
 182    }
 183
 184    /* keep searching in the hot buffers */
 185    if (!entry && ret != -1) {
 186       while (cur != cache) {
 187          cur_entry = LIST_ENTRY(struct pb_cache_entry, cur, head);
 188          ret = pb_cache_is_buffer_compat(cur_entry, size, alignment, usage);
 189
 190          if (ret > 0) {
 191             entry = cur_entry;
 192             break;
 193          }
 194          if (ret == -1)
 195             break;
 196          /* no need to check the timeout here */
 197          cur = next;
 198          next = cur->next;
 199       }
 200    }
 201
 202    /* found a compatible buffer, return it */
 203    if (entry) {
 204       struct pb_buffer *buf = entry->buffer;
 205
 206       mgr->cache_size -= buf->size;
 207       LIST_DEL(&entry->head);
 208       --mgr->num_buffers;
 209       pipe_mutex_unlock(mgr->mutex);
 210       /* Increase refcount */
 211       pipe_reference_init(&buf->reference, 1);
 212       return buf;
 213    }
 214
 215    pipe_mutex_unlock(mgr->mutex);
 216    return NULL;
 217 }
 218
 219 /**
 220  * Empty the cache. Useful when there is not enough memory.
 221  */
 222 void
 223 pb_cache_release_all_buffers(struct pb_cache *mgr)
 224 {
 225    struct list_head *curr, *next;
 226    struct pb_cache_entry *buf;
 227    unsigned i;
 228
 229    pipe_mutex_lock(mgr->mutex);
 230    for (i = 0; i < ARRAY_SIZE(mgr->buckets); i++) {
 231       struct list_head *cache = &mgr->buckets[i];
 232
 233       curr = cache->next;
 234       next = curr->next;
 235       while (curr != cache) {
 236          buf = LIST_ENTRY(struct pb_cache_entry, curr, head);
 237          destroy_buffer_locked(buf);
 238          curr = next;
 239          next = curr->next;
 240       }
 241    }
 242    pipe_mutex_unlock(mgr->mutex);
 243 }
 244
 245 void
 246 pb_cache_init_entry(struct pb_cache *mgr, struct pb_cache_entry *entry,
 247                     struct pb_buffer *buf, unsigned bucket_index)
 248 {
 249    memset(entry, 0, sizeof(*entry));
 250    entry->buffer = buf;
 251    entry->mgr = mgr;
 252    entry->bucket_index = bucket_index;
 253 }
 254
 255 /**
 256  * Initialize a caching buffer manager.
 257  *
 258  * @param mgr     The cache buffer manager
 259  * @param usecs   Unused buffers may be released from the cache after this
 260  *                time
 261  * @param size_factor  Declare buffers that are size_factor times bigger than
 262  *                     the requested size as cache hits.
 263  * @param bypass_usage  Bitmask. If (requested usage & bypass_usage) != 0,
 264  *                      buffer allocation requests are rejected.
 265  * @param maximum_cache_size  Maximum size of all unused buffers the cache can
 266  *                            hold.
 267  * @param destroy_buffer  Function that destroys a buffer for good.
 268  * @param can_reclaim     Whether a buffer can be reclaimed (e.g. is not busy)
 269  */
 270 void
 271 pb_cache_init(struct pb_cache *mgr, uint usecs, float size_factor,
 272               unsigned bypass_usage, uint64_t maximum_cache_size,
 273               void (*destroy_buffer)(struct pb_buffer *buf),
 274               bool (*can_reclaim)(struct pb_buffer *buf))
 275 {
 276    unsigned i;
 277
 278    for (i = 0; i < ARRAY_SIZE(mgr->buckets); i++)
 279       LIST_INITHEAD(&mgr->buckets[i]);
 280
 281    pipe_mutex_init(mgr->mutex);
 282    mgr->cache_size = 0;
 283    mgr->max_cache_size = maximum_cache_size;
 284    mgr->usecs = usecs;
 285    mgr->num_buffers = 0;
 286    mgr->bypass_usage = bypass_usage;
 287    mgr->size_factor = size_factor;
 288    mgr->destroy_buffer = destroy_buffer;
 289    mgr->can_reclaim = can_reclaim;
 290 }
 291
 292 /**
 293  * Deinitialize the manager completely.
 294  */
 295 void
 296 pb_cache_deinit(struct pb_cache *mgr)
 297 {
 298    pb_cache_release_all_buffers(mgr);
 299    pipe_mutex_destroy(mgr->mutex);
 300 }