[Mesa-dev] [PATCH 2/3] Revert "disk cache: initialize cache path and index only when used"

Marek Olšák maraeo at gmail.com
Mon Feb 12 15:53:44 UTC 2018


radeonsi uses the shader cache from multiple threads.

Marek

On Fri, Feb 9, 2018 at 4:59 AM, Timothy Arceri <tarceri at itsqueeze.com> wrote:
> This reverts commit 6a651b6b77b68db71a027c826abccc843ace88ef.
>
> This change was not thread safe. Applications are allowed to compile
> multiple programs attached to the same context in different threads
> which means we can end up with multiple threads inside
> disk_cache_path_init() or thinking disk_cache_path_init() has
> completed when it hasn't causing various problems.
>
> This change was also causing piglit runs to deadlock with radeonsi
> on a Ryzen 1800X (8 cores), I don't believe shader runner does
> threaded compiles so I'm unsure of the exact root of this additional
> problem.
> ---
>  src/util/disk_cache.c | 129 +++++++++++++++++++-------------------------------
>  1 file changed, 49 insertions(+), 80 deletions(-)
>
> diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
> index dec5a67a79..2884d3c9c1 100644
> --- a/src/util/disk_cache.c
> +++ b/src/util/disk_cache.c
> @@ -77,7 +77,6 @@
>  struct disk_cache {
>     /* The path to the cache directory. */
>     char *path;
> -   bool path_init_failed;
>
>     /* Thread queue for compressing and writing cache entries to disk */
>     struct util_queue cache_queue;
> @@ -179,20 +178,37 @@ concatenate_and_mkdir(void *ctx, const char *path, const char *name)
>        return NULL;
>  }
>
> -static bool
> -disk_cache_path_init(struct disk_cache *cache)
> +#define DRV_KEY_CPY(_dst, _src, _src_size) \
> +do {                                       \
> +   memcpy(_dst, _src, _src_size);          \
> +   _dst += _src_size;                      \
> +} while (0);
> +
> +struct disk_cache *
> +disk_cache_create(const char *gpu_name, const char *timestamp,
> +                  uint64_t driver_flags)
>  {
> -   void *local = NULL;
> -   char *path;
> +   void *local;
> +   struct disk_cache *cache = NULL;
> +   char *path, *max_size_str;
> +   uint64_t max_size;
>     int fd = -1;
>     struct stat sb;
>     size_t size;
>
> +   /* If running as a users other than the real user disable cache */
> +   if (geteuid() != getuid())
> +      return NULL;
> +
>     /* A ralloc context for transient data during this invocation. */
>     local = ralloc_context(NULL);
>     if (local == NULL)
>        goto fail;
>
> +   /* At user request, disable shader cache entirely. */
> +   if (env_var_as_boolean("MESA_GLSL_CACHE_DISABLE", false))
> +      goto fail;
> +
>     /* Determine path for cache based on the first defined name as follows:
>      *
>      *   $MESA_GLSL_CACHE_DIR
> @@ -257,6 +273,10 @@ disk_cache_path_init(struct disk_cache *cache)
>           goto fail;
>     }
>
> +   cache = ralloc(NULL, struct disk_cache);
> +   if (cache == NULL)
> +      goto fail;
> +
>     cache->path = ralloc_strdup(cache, path);
>     if (cache->path == NULL)
>        goto fail;
> @@ -305,58 +325,6 @@ disk_cache_path_init(struct disk_cache *cache)
>     cache->size = (uint64_t *) cache->index_mmap;
>     cache->stored_keys = cache->index_mmap + sizeof(uint64_t);
>
> -   /* 1 thread was chosen because we don't really care about getting things
> -    * to disk quickly just that it's not blocking other tasks.
> -    *
> -    * The queue will resize automatically when it's full, so adding new jobs
> -    * doesn't stall.
> -    */
> -   util_queue_init(&cache->cache_queue, "disk_cache", 32, 1,
> -                   UTIL_QUEUE_INIT_RESIZE_IF_FULL |
> -                   UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY);
> -
> -   ralloc_free(local);
> -
> -   return true;
> -
> - fail:
> -   if (fd != -1)
> -      close(fd);
> -
> -   if (local)
> -      ralloc_free(local);
> -
> -   cache->path_init_failed = true;
> -
> -   return false;
> -}
> -
> -#define DRV_KEY_CPY(_dst, _src, _src_size) \
> -do {                                       \
> -   memcpy(_dst, _src, _src_size);          \
> -   _dst += _src_size;                      \
> -} while (0);
> -
> -struct disk_cache *
> -disk_cache_create(const char *gpu_name, const char *timestamp,
> -                  uint64_t driver_flags)
> -{
> -   struct disk_cache *cache = NULL;
> -   char *max_size_str;
> -   uint64_t max_size;
> -
> -   /* If running as a users other than the real user disable cache */
> -   if (geteuid() != getuid())
> -      return NULL;
> -
> -   /* At user request, disable shader cache entirely. */
> -   if (env_var_as_boolean("MESA_GLSL_CACHE_DISABLE", false))
> -      return NULL;
> -
> -   cache = rzalloc(NULL, struct disk_cache);
> -   if (cache == NULL)
> -      return NULL;
> -
>     max_size = 0;
>
>     max_size_str = getenv("MESA_GLSL_CACHE_MAX_SIZE");
> @@ -392,6 +360,16 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
>
>     cache->max_size = max_size;
>
> +   /* 1 thread was chosen because we don't really care about getting things
> +    * to disk quickly just that it's not blocking other tasks.
> +    *
> +    * The queue will resize automatically when it's full, so adding new jobs
> +    * doesn't stall.
> +    */
> +   util_queue_init(&cache->cache_queue, "disk_cache", 32, 1,
> +                   UTIL_QUEUE_INIT_RESIZE_IF_FULL |
> +                   UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY);
> +
>     uint8_t cache_version = CACHE_VERSION;
>     size_t cv_size = sizeof(cache_version);
>     cache->driver_keys_blob_size = cv_size;
> @@ -414,10 +392,8 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
>
>     cache->driver_keys_blob =
>        ralloc_size(cache, cache->driver_keys_blob_size);
> -   if (!cache->driver_keys_blob) {
> -      ralloc_free(cache);
> -      return NULL;
> -   }
> +   if (!cache->driver_keys_blob)
> +      goto fail;
>
>     uint8_t *drv_key_blob = cache->driver_keys_blob;
>     DRV_KEY_CPY(drv_key_blob, &cache_version, cv_size)
> @@ -429,13 +405,24 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
>     /* Seed our rand function */
>     s_rand_xorshift128plus(cache->seed_xorshift128plus, true);
>
> +   ralloc_free(local);
> +
>     return cache;
> +
> + fail:
> +   if (fd != -1)
> +      close(fd);
> +   if (cache)
> +      ralloc_free(cache);
> +   ralloc_free(local);
> +
> +   return NULL;
>  }
>
>  void
>  disk_cache_destroy(struct disk_cache *cache)
>  {
> -   if (cache && cache->index_mmap) {
> +   if (cache) {
>        util_queue_destroy(&cache->cache_queue);
>        munmap(cache->index_mmap, cache->index_mmap_size);
>     }
> @@ -454,9 +441,6 @@ get_cache_file(struct disk_cache *cache, const cache_key key)
>     char buf[41];
>     char *filename;
>
> -   if (!cache->path)
> -      return NULL;
> -
>     _mesa_sha1_format(buf, key);
>     if (asprintf(&filename, "%s/%c%c/%s", cache->path, buf[0],
>                  buf[1], buf + 2) == -1)
> @@ -1012,11 +996,6 @@ disk_cache_put(struct disk_cache *cache, const cache_key key,
>                 const void *data, size_t size,
>                 struct cache_item_metadata *cache_item_metadata)
>  {
> -   /* Initialize path if not initialized yet. */
> -   if (cache->path_init_failed ||
> -       (!cache->path && !disk_cache_path_init(cache)))
> -      return;
> -
>     struct disk_cache_put_job *dc_job =
>        create_put_job(cache, key, data, size, cache_item_metadata);
>
> @@ -1194,11 +1173,6 @@ disk_cache_put_key(struct disk_cache *cache, const cache_key key)
>     int i = CPU_TO_LE32(*key_chunk) & CACHE_INDEX_KEY_MASK;
>     unsigned char *entry;
>
> -   if (!cache->path) {
> -      assert(!"disk_cache_put_key called with no path set");
> -      return;
> -   }
> -
>     entry = &cache->stored_keys[i * CACHE_KEY_SIZE];
>
>     memcpy(entry, key, CACHE_KEY_SIZE);
> @@ -1218,11 +1192,6 @@ disk_cache_has_key(struct disk_cache *cache, const cache_key key)
>     int i = CPU_TO_LE32(*key_chunk) & CACHE_INDEX_KEY_MASK;
>     unsigned char *entry;
>
> -   /* Initialize path if not initialized yet. */
> -   if (cache->path_init_failed ||
> -       (!cache->path && !disk_cache_path_init(cache)))
> -      return false;
> -
>     entry = &cache->stored_keys[i * CACHE_KEY_SIZE];
>
>     return memcmp(entry, key, CACHE_KEY_SIZE) == 0;
> --
> 2.14.3
>
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