[Mesa-dev] [PATCH 3/5] disk cache: initialize cache path and index only when used

[Tapani Pälli]

This patch makes disk_cache initialize path and index lazily so
that we can utilize disk_cache without a path using callback
functionality introduced by next patch.

Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
---
 src/util/disk_cache.c | 114 ++++++++++++++++++++++++++++++++------------------
 1 file changed, 73 insertions(+), 41 deletions(-)

diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
index 2884d3c9c1..2fb07699b5 100644
--- a/src/util/disk_cache.c
+++ b/src/util/disk_cache.c
@@ -77,6 +77,7 @@
 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;
@@ -178,27 +179,18 @@ concatenate_and_mkdir(void *ctx, const char *path, const char *name)
       return NULL;
 }
 
-#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)
+static bool
+disk_cache_path_init(struct disk_cache *cache)
 {
-   void *local;
-   struct disk_cache *cache = NULL;
-   char *path, *max_size_str;
-   uint64_t max_size;
+   void *local = NULL;
+   char *path;
    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;
+      goto fail;
 
    /* A ralloc context for transient data during this invocation. */
    local = ralloc_context(NULL);
@@ -273,10 +265,6 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
          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;
@@ -325,6 +313,58 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
    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");
@@ -360,16 +400,6 @@ 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;
@@ -392,8 +422,10 @@ 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)
-      goto fail;
+   if (!cache->driver_keys_blob) {
+      ralloc_free(cache);
+      return NULL;
+   }
 
    uint8_t *drv_key_blob = cache->driver_keys_blob;
    DRV_KEY_CPY(drv_key_blob, &cache_version, cv_size)
@@ -405,18 +437,7 @@ 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
@@ -441,6 +462,9 @@ 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)
@@ -1173,6 +1197,9 @@ 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)
+      return;
+
    entry = &cache->stored_keys[i * CACHE_KEY_SIZE];
 
    memcpy(entry, key, CACHE_KEY_SIZE);
@@ -1192,6 +1219,11 @@ 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;
 
+   /* Try initializing path only once. */
+   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