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    struct pb_buffer *buf = entry->buffer;
  42
  43    assert(!pipe_is_referenced(&buf->reference));
  44    if (entry->head.next) {
  45       LIST_DEL(&entry->head);
  46       assert(mgr->num_buffers);
  47       --mgr->num_buffers;
  48       mgr->cache_size -= buf->size;
  49    }
  50    mgr->destroy_buffer(buf);
  51 }
  52
  53 /**
  54  * Free as many cache buffers from the list head as possible.
  55  */
  56 static void
  57 release_expired_buffers_locked(struct list_head *cache)
  58 {
  59    struct list_head *curr, *next;
  60    struct pb_cache_entry *entry;
  61    int64_t now;
  62
  63    now = os_time_get();
  64
  65    curr = cache->next;
  66    next = curr->next;
  67    while (curr != cache) {
  68       entry = LIST_ENTRY(struct pb_cache_entry, curr, head);
  69
  70       if (!os_time_timeout(entry->start, entry->end, now))
  71          break;
  72
  73       destroy_buffer_locked(entry);
  74
  75       curr = next;
  76       next = curr->next;
  77    }
  78 }
  79
  80 /**
  81  * Add a buffer to the cache. This is typically done when the buffer is
  82  * being released.
  83  */
  84 void
  85 pb_cache_add_buffer(struct pb_cache_entry *entry)
  86 {
  87    struct pb_cache *mgr = entry->mgr;
  88    struct list_head *cache = &mgr->buckets[entry->bucket_index];
  89    struct pb_buffer *buf = entry->buffer;
  90    unsigned i;
  91
  92    pipe_mutex_lock(mgr->mutex);
  93    assert(!pipe_is_referenced(&buf->reference));
  94
  95    for (i = 0; i < ARRAY_SIZE(mgr->buckets); i++)
  96       release_expired_buffers_locked(&mgr->buckets[i]);
  97
  98    /* Directly release any buffer that exceeds the limit. */
  99    if (mgr->cache_size + buf->size > mgr->max_cache_size) {
 100       mgr->destroy_buffer(buf);
 101       pipe_mutex_unlock(mgr->mutex);
 102       return;
 103    }
 104
 105    entry->start = os_time_get();
 106    entry->end = entry->start + mgr->usecs;
 107    LIST_ADDTAIL(&entry->head, cache);
 108    ++mgr->num_buffers;
 109    mgr->cache_size += buf->size;
 110    pipe_mutex_unlock(mgr->mutex);
 111 }
 112
 113 /**
 114  * \return 1   if compatible and can be reclaimed
 115  *         0   if incompatible
 116  *        -1   if compatible and can't be reclaimed
 117  */
 118 static int
 119 pb_cache_is_buffer_compat(struct pb_cache_entry *entry,
 120                           pb_size size, unsigned alignment, unsigned usage)
 121 {
 122    struct pb_cache *mgr = entry->mgr;
 123    struct pb_buffer *buf = entry->buffer;
 124
 125    if (!pb_check_usage(usage, buf->usage))
 126       return 0;
 127
 128    /* be lenient with size */
 129    if (buf->size < size ||
 130        buf->size > (unsigned) (mgr->size_factor * size))
 131       return 0;
 132
 133    if (usage & mgr->bypass_usage)
 134       return 0;
 135
 136    if (!pb_check_alignment(alignment, buf->alignment))
 137       return 0;
 138
 139    return mgr->can_reclaim(buf) ? 1 : -1;
 140 }
 141
 142 /**
 143  * Find a compatible buffer in the cache, return it, and remove it
 144  * from the cache.
 145  */
 146 struct pb_buffer *
 147 pb_cache_reclaim_buffer(struct pb_cache *mgr, pb_size size,
 148                         unsigned alignment, unsigned usage,
 149                         unsigned bucket_index)
 150 {
 151    struct pb_cache_entry *entry;
 152    struct pb_cache_entry *cur_entry;
 153    struct list_head *cur, *next;
 154    int64_t now;
 155    int ret = 0;
 156    struct list_head *cache = &mgr->buckets[bucket_index];
 157
 158    pipe_mutex_lock(mgr->mutex);
 159
 160    entry = NULL;
 161    cur = cache->next;
 162    next = cur->next;
 163
 164    /* search in the expired buffers, freeing them in the process */
 165    now = os_time_get();
 166    while (cur != cache) {
 167       cur_entry = LIST_ENTRY(struct pb_cache_entry, cur, head);
 168
 169       if (!entry && (ret = pb_cache_is_buffer_compat(cur_entry, size,
 170                                                      alignment, usage) > 0))
 171          entry = cur_entry;
 172       else if (os_time_timeout(cur_entry->start, cur_entry->end, now))
 173          destroy_buffer_locked(cur_entry);
 174       else
 175          /* This buffer (and all hereafter) are still hot in cache */
 176          break;
 177
 178       /* the buffer is busy (and probably all remaining ones too) */
 179       if (ret == -1)
 180          break;
 181
 182       cur = next;
 183       next = cur->next;
 184    }
 185
 186    /* keep searching in the hot buffers */
 187    if (!entry && ret != -1) {
 188       while (cur != cache) {
 189          cur_entry = LIST_ENTRY(struct pb_cache_entry, cur, head);
 190          ret = pb_cache_is_buffer_compat(cur_entry, size, alignment, usage);
 191
 192          if (ret > 0) {
 193             entry = cur_entry;
 194             break;
 195          }
 196          if (ret == -1)
 197             break;
 198          /* no need to check the timeout here */
 199          cur = next;
 200          next = cur->next;
 201       }
 202    }
 203
 204    /* found a compatible buffer, return it */
 205    if (entry) {
 206       struct pb_buffer *buf = entry->buffer;
 207
 208       mgr->cache_size -= buf->size;
 209       LIST_DEL(&entry->head);
 210       --mgr->num_buffers;
 211       pipe_mutex_unlock(mgr->mutex);
 212       /* Increase refcount */
 213       pipe_reference_init(&buf->reference, 1);
 214       return buf;
 215    }
 216
 217    pipe_mutex_unlock(mgr->mutex);
 218    return NULL;
 219 }
 220
 221 /**
 222  * Empty the cache. Useful when there is not enough memory.
 223  */
 224 void
 225 pb_cache_release_all_buffers(struct pb_cache *mgr)
 226 {
 227    struct list_head *curr, *next;
 228    struct pb_cache_entry *buf;
 229    unsigned i;
 230
 231    pipe_mutex_lock(mgr->mutex);
 232    for (i = 0; i < ARRAY_SIZE(mgr->buckets); i++) {
 233       struct list_head *cache = &mgr->buckets[i];
 234
 235       curr = cache->next;
 236       next = curr->next;
 237       while (curr != cache) {
 238          buf = LIST_ENTRY(struct pb_cache_entry, curr, head);
 239          destroy_buffer_locked(buf);
 240          curr = next;
 241          next = curr->next;
 242       }
 243    }
 244    pipe_mutex_unlock(mgr->mutex);
 245 }
 246
 247 void
 248 pb_cache_init_entry(struct pb_cache *mgr, struct pb_cache_entry *entry,
 249                     struct pb_buffer *buf, unsigned bucket_index)
 250 {
 251    memset(entry, 0, sizeof(*entry));
 252    entry->buffer = buf;
 253    entry->mgr = mgr;
 254    entry->bucket_index = bucket_index;
 255 }
 256
 257 /**
 258  * Initialize a caching buffer manager.
 259  *
 260  * @param mgr     The cache buffer manager
 261  * @param usecs   Unused buffers may be released from the cache after this
 262  *                time
 263  * @param size_factor  Declare buffers that are size_factor times bigger than
 264  *                     the requested size as cache hits.
 265  * @param bypass_usage  Bitmask. If (requested usage & bypass_usage) != 0,
 266  *                      buffer allocation requests are rejected.
 267  * @param maximum_cache_size  Maximum size of all unused buffers the cache can
 268  *                            hold.
 269  * @param destroy_buffer  Function that destroys a buffer for good.
 270  * @param can_reclaim     Whether a buffer can be reclaimed (e.g. is not busy)
 271  */
 272 void
 273 pb_cache_init(struct pb_cache *mgr, uint usecs, float size_factor,
 274               unsigned bypass_usage, uint64_t maximum_cache_size,
 275               void (*destroy_buffer)(struct pb_buffer *buf),
 276               bool (*can_reclaim)(struct pb_buffer *buf))
 277 {
 278    unsigned i;
 279
 280    for (i = 0; i < ARRAY_SIZE(mgr->buckets); i++)
 281       LIST_INITHEAD(&mgr->buckets[i]);
 282
 283    pipe_mutex_init(mgr->mutex);
 284    mgr->cache_size = 0;
 285    mgr->max_cache_size = maximum_cache_size;
 286    mgr->usecs = usecs;
 287    mgr->num_buffers = 0;
 288    mgr->bypass_usage = bypass_usage;
 289    mgr->size_factor = size_factor;
 290    mgr->destroy_buffer = destroy_buffer;
 291    mgr->can_reclaim = can_reclaim;
 292 }
 293
 294 /**
 295  * Deinitialize the manager completely.
 296  */
 297 void
 298 pb_cache_deinit(struct pb_cache *mgr)
 299 {
 300    pb_cache_release_all_buffers(mgr);
 301    pipe_mutex_destroy(mgr->mutex);
 302 }