From f2b37132cb6a804b958d2e1dff17e7d77e430b96 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristian=20H=C3=B8gsberg=20Kristensen?=
 <kristian.h.kristensen@intel.com>
Date: Sat, 5 Mar 2016 12:20:16 -0800
Subject: [PATCH] anv: Check if shader if present before uploading to cache

Between the initial check the returns NO_KERNEL and compiling the
shader, other threads may have added the shader to the cache. Before
uploading the kernel, check again (under the mutex) that the compiled
shader still isn't present.
---
 src/intel/vulkan/anv_pipeline_cache.c | 45 ++++++++++++++++++++++-----
 1 file changed, 38 insertions(+), 7 deletions(-)

diff --git a/src/intel/vulkan/anv_pipeline_cache.c b/src/intel/vulkan/anv_pipeline_cache.c
index 3d2429a4e2a..f7a1e1c679a 100644
--- a/src/intel/vulkan/anv_pipeline_cache.c
+++ b/src/intel/vulkan/anv_pipeline_cache.c
@@ -116,11 +116,11 @@ anv_hash_shader(unsigned char *hash, const void *key, size_t key_size,
    _mesa_sha1_final(ctx, hash);
 }
 
-uint32_t
-anv_pipeline_cache_search(struct anv_pipeline_cache *cache,
-                          const unsigned char *sha1,
-                          const struct brw_stage_prog_data **prog_data,
-                          struct anv_pipeline_bind_map *map)
+static uint32_t
+anv_pipeline_cache_search_unlocked(struct anv_pipeline_cache *cache,
+                                   const unsigned char *sha1,
+                                   const struct brw_stage_prog_data **prog_data,
+                                   struct anv_pipeline_bind_map *map)
 {
    const uint32_t mask = cache->table_size - 1;
    const uint32_t start = (*(uint32_t *) sha1);
@@ -152,7 +152,24 @@ anv_pipeline_cache_search(struct anv_pipeline_cache *cache,
       }
    }
 
-   return NO_KERNEL;
+   unreachable("hash table should never be full");
+}
+
+uint32_t
+anv_pipeline_cache_search(struct anv_pipeline_cache *cache,
+                          const unsigned char *sha1,
+                          const struct brw_stage_prog_data **prog_data,
+                          struct anv_pipeline_bind_map *map)
+{
+   uint32_t kernel;
+
+   pthread_mutex_lock(&cache->mutex);
+
+   kernel = anv_pipeline_cache_search_unlocked(cache, sha1, prog_data, map);
+
+   pthread_mutex_unlock(&cache->mutex);
+
+   return kernel;
 }
 
 static void
@@ -234,6 +251,19 @@ anv_pipeline_cache_upload_kernel(struct anv_pipeline_cache *cache,
                                  struct anv_pipeline_bind_map *map)
 {
    pthread_mutex_lock(&cache->mutex);
+
+   /* Before uploading, check again that another thread didn't upload this
+    * shader while we were compiling it.
+    */
+   if (sha1) {
+      uint32_t cached_kernel =
+         anv_pipeline_cache_search_unlocked(cache, sha1, prog_data, map);
+      if (cached_kernel != NO_KERNEL) {
+         pthread_mutex_unlock(&cache->mutex);
+         return cached_kernel;
+      }
+   }
+
    struct cache_entry *entry;
 
    const uint32_t map_size =
@@ -270,7 +300,8 @@ anv_pipeline_cache_upload_kernel(struct anv_pipeline_cache *cache,
    map->sampler_to_descriptor = p;
 
    if (sha1 && env_var_as_boolean("ANV_ENABLE_PIPELINE_CACHE", false)) {
-      assert(anv_pipeline_cache_search(cache, sha1, NULL, NULL) == NO_KERNEL);
+      assert(anv_pipeline_cache_search_unlocked(cache, sha1,
+                                                NULL, NULL) == NO_KERNEL);
 
       memcpy(entry->sha1, sha1, sizeof(entry->sha1));
       anv_pipeline_cache_add_entry(cache, entry, state.offset);