Steam is already analysing cache items, unfortunatly we did not
introduce a versioning mechanism for identifying structural changes
to cache entries earlier so the only way to do so is to rename the
cache directory.
Since we are renaming it we take the opportunity to give the directory
a more meaningful name.
Adding a version field to the header of cache entries will help us to
avoid having to rename the directory in future. Please note this is
versioning for the internal structure of the entries as defined in
disk_cache.{c,h} as opposed to the structure of the data provided to
the disk cache by the GLSL compiler and the various driver backends.
---
src/compiler/glsl/tests/cache_test.c | 6 +++--
src/util/disk_cache.c | 46 ++++++++++++++++++++++++++----------
src/util/disk_cache.h | 2 ++
3 files changed, 40 insertions(+), 14 deletions(-)
diff --git a/src/compiler/glsl/tests/cache_test.c
b/src/compiler/glsl/tests/cache_test.c
index af1b66fb3d..3796ce6170 100644
--- a/src/compiler/glsl/tests/cache_test.c
+++ b/src/compiler/glsl/tests/cache_test.c
@@ -178,38 +178,40 @@ test_disk_cache_create(void)
/* Test with XDG_CACHE_HOME set */
setenv("XDG_CACHE_HOME", CACHE_TEST_TMP "/xdg-cache-home", 1);
cache = disk_cache_create("test", "make_check", 0);
expect_null(cache, "disk_cache_create with XDG_CACHE_HOME set with"
"a non-existing parent directory");
mkdir(CACHE_TEST_TMP, 0755);
cache = disk_cache_create("test", "make_check", 0);
expect_non_null(cache, "disk_cache_create with XDG_CACHE_HOME set");
- check_directories_created(CACHE_TEST_TMP "/xdg-cache-home/mesa");
+ check_directories_created(CACHE_TEST_TMP "/xdg-cache-home/"
+ CACHE_DIR_NAME);
disk_cache_destroy(cache);
/* Test with MESA_GLSL_CACHE_DIR set */
err = rmrf_local(CACHE_TEST_TMP);
expect_equal(err, 0, "Removing " CACHE_TEST_TMP);
setenv("MESA_GLSL_CACHE_DIR", CACHE_TEST_TMP "/mesa-glsl-cache-dir", 1);
cache = disk_cache_create("test", "make_check", 0);
expect_null(cache, "disk_cache_create with MESA_GLSL_CACHE_DIR set with"
"a non-existing parent directory");
mkdir(CACHE_TEST_TMP, 0755);
cache = disk_cache_create("test", "make_check", 0);
expect_non_null(cache, "disk_cache_create with MESA_GLSL_CACHE_DIR set");
- check_directories_created(CACHE_TEST_TMP "/mesa-glsl-cache-dir/mesa");
+ check_directories_created(CACHE_TEST_TMP "/mesa-glsl-cache-dir/"
+ CACHE_DIR_NAME);
disk_cache_destroy(cache);
}
static bool
does_cache_contain(struct disk_cache *cache, const cache_key key)
{
void *result;
result = disk_cache_get(cache, key, NULL);
diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
index b2229874e0..644a911e53 100644
--- a/src/util/disk_cache.c
+++ b/src/util/disk_cache.c
@@ -51,20 +51,34 @@
/* Number of bits to mask off from a cache key to get an index. */
#define CACHE_INDEX_KEY_BITS 16
/* Mask for computing an index from a key. */
#define CACHE_INDEX_KEY_MASK ((1 << CACHE_INDEX_KEY_BITS) - 1)
/* The number of keys that can be stored in the index. */
#define CACHE_INDEX_MAX_KEYS (1 << CACHE_INDEX_KEY_BITS)
+/* The cache version should be bumped whenever a change is made to the
+ * structure of cache entries or the index. This will give any 3rd party
+ * applications reading the cache entries a chance to adjust to the changes.
+ *
+ * - The cache version is checked internally when reading a cache entry. If we
+ * ever have a mismatch we are in big trouble as this means we had a cache
+ * collision. In case of such an event please check the skys for giant
+ * asteroids and that the entire Mesa team hasn't been eaten by wolves.
+ *
+ * - There is no strict requirement that cache versions be backwards
+ * compatible but effort should be taken to limit disruption where possible.
+ */
+#define CACHE_VERSION 1
+
struct disk_cache {
/* The path to the cache directory. */
char *path;
/* Thread queue for compressing and writing cache entries to disk */
struct util_queue cache_queue;
/* Seed for rand, which is used to pick a random directory */
uint64_t seed_xorshift128plus[2];
@@ -153,20 +167,25 @@ concatenate_and_mkdir(void *ctx, const char *path, const
char *name)
return NULL;
new_path = ralloc_asprintf(ctx, "%s/%s", path, name);
if (mkdir_if_needed(new_path) == 0)
return new_path;
else
return NULL;
}
+#define DRV_KEY_CPY(_dst, _src, _src_size) { \
+ 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;
struct disk_cache *cache = NULL;
char *path, *max_size_str;
uint64_t max_size;
int fd = -1;
struct stat sb;
@@ -181,41 +200,41 @@ disk_cache_create(const char *gpu_name, const char
*timestamp,
if (local == NULL)
goto fail;
/* At user request, disable shader cache entirely. */
if (getenv("MESA_GLSL_CACHE_DISABLE"))
goto fail;
/* Determine path for cache based on the first defined name as follows:
*
* $MESA_GLSL_CACHE_DIR
- * $XDG_CACHE_HOME/mesa
- * <pwd.pw_dir>/.cache/mesa
+ * $XDG_CACHE_HOME/mesa_shader_cache
+ * <pwd.pw_dir>/.cache/mesa_shader_cache
*/
path = getenv("MESA_GLSL_CACHE_DIR");
if (path) {
if (mkdir_if_needed(path) == -1)
goto fail;
- path = concatenate_and_mkdir(local, path, "mesa");
+ path = concatenate_and_mkdir(local, path, CACHE_DIR_NAME);
if (path == NULL)
goto fail;
}
if (path == NULL) {
char *xdg_cache_home = getenv("XDG_CACHE_HOME");
if (xdg_cache_home) {
if (mkdir_if_needed(xdg_cache_home) == -1)
goto fail;
- path = concatenate_and_mkdir(local, xdg_cache_home, "mesa");
+ path = concatenate_and_mkdir(local, xdg_cache_home, CACHE_DIR_NAME);
if (path == NULL)
goto fail;
}
}
if (path == NULL) {
char *buf;
size_t buf_size;
struct passwd pwd, *result;
@@ -237,21 +256,21 @@ disk_cache_create(const char *gpu_name, const char
*timestamp,
buf_size *= 2;
} else {
goto fail;
}
}
path = concatenate_and_mkdir(local, pwd.pw_dir, ".cache");
if (path == NULL)
goto fail;
- path = concatenate_and_mkdir(local, path, "mesa");
+ path = concatenate_and_mkdir(local, path, CACHE_DIR_NAME);
if (path == NULL)
goto fail;
}
cache = ralloc(NULL, struct disk_cache);
if (cache == NULL)
goto fail;
cache->path = ralloc_strdup(cache, path);
if (cache->path == NULL)
@@ -337,47 +356,50 @@ disk_cache_create(const char *gpu_name, const char
*timestamp,
cache->max_size = max_size;
/* A limit of 32 jobs was choosen as observations of Deus Ex start-up times
* showed that we reached at most 11 jobs on an Intel i5-6400 CPU@2.70GHz
* (a fairly modest desktop CPU). 1 thread was chosen because we don't
* really care about getting things to disk quickly just that it's not
* blocking other tasks.
*/
util_queue_init(&cache->cache_queue, "disk_cache", 32, 1, 0);
+ uint8_t cache_version = CACHE_VERSION;
+ size_t cv_size = sizeof(cache_version);
+ cache->driver_keys_blob_size = cv_size;
+
/* Create driver id keys */
size_t ts_size = strlen(timestamp) + 1;
size_t gpu_name_size = strlen(gpu_name) + 1;
- cache->driver_keys_blob_size = ts_size;
+ cache->driver_keys_blob_size += ts_size;
cache->driver_keys_blob_size += gpu_name_size;
/* We sometimes store entire structs that contains a pointers in the cache,
* use pointer size as a key to avoid hard to debug issues.
*/
uint8_t ptr_size = sizeof(void *);
size_t ptr_size_size = sizeof(ptr_size);
cache->driver_keys_blob_size += ptr_size_size;
size_t driver_flags_size = sizeof(driver_flags);
cache->driver_keys_blob_size += driver_flags_size;
cache->driver_keys_blob =
ralloc_size(cache, cache->driver_keys_blob_size);
if (!cache->driver_keys_blob)
goto fail;
- memcpy(cache->driver_keys_blob, timestamp, ts_size);
- memcpy(cache->driver_keys_blob + ts_size, gpu_name, gpu_name_size);
- memcpy(cache->driver_keys_blob + ts_size + gpu_name_size, &ptr_size,
- ptr_size_size);
- memcpy(cache->driver_keys_blob + ts_size + gpu_name_size + ptr_size_size,
- &driver_flags, driver_flags_size);
+ DRV_KEY_CPY(cache->driver_keys_blob, &cache_version, cv_size)
+ DRV_KEY_CPY(cache->driver_keys_blob, timestamp, ts_size)
+ DRV_KEY_CPY(cache->driver_keys_blob, gpu_name, gpu_name_size)
+ DRV_KEY_CPY(cache->driver_keys_blob, &ptr_size, ptr_size_size)
+ DRV_KEY_CPY(cache->driver_keys_blob, &driver_flags, driver_flags_size)
/* Seed our rand function */
s_rand_xorshift128plus(cache->seed_xorshift128plus, true);
ralloc_free(local);
return cache;
fail:
if (fd != -1)
diff --git a/src/util/disk_cache.h b/src/util/disk_cache.h
index 9aade16a9e..3521ef4a6b 100644
--- a/src/util/disk_cache.h
+++ b/src/util/disk_cache.h
@@ -32,20 +32,22 @@
#include <stdbool.h>
#include <sys/stat.h>
#ifdef __cplusplus
extern "C" {
#endif
/* Size of cache keys in bytes. */
#define CACHE_KEY_SIZE 20
+#define CACHE_DIR_NAME "mesa_shader_cache"
+
typedef uint8_t cache_key[CACHE_KEY_SIZE];
struct disk_cache;
static inline bool
disk_cache_get_function_timestamp(void *ptr, uint32_t* timestamp)
{
#ifdef ENABLE_SHADER_CACHE
Dl_info info;
struct stat st;
--
2.13.4
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