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