[Mesa-dev] [PATCH 1/2] util/disk_cache: support caches for multiple architectures

[Ilia Mirkin]

On Thu, Mar 2, 2017 at 1:08 AM, Timothy Arceri <tarceri at itsqueeze.com> wrote:
> Previously we were deleting the entire cache if a user switched
> between 32 and 64 bit applications.
> ---
>  src/util/disk_cache.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
> index 3abdec4..1a91c69 100644
> --- a/src/util/disk_cache.c
> +++ b/src/util/disk_cache.c
> @@ -40,20 +40,32 @@
>  #include "zlib.h"
>
>  #include "util/crc32.h"
>  #include "util/u_atomic.h"
>  #include "util/mesa-sha1.h"
>  #include "util/ralloc.h"
>  #include "main/errors.h"
>
>  #include "disk_cache.h"
>
> +#if defined(__x86_64__)
> +#if defined(__ILP32__)
> +#define CACHE_ARCH "x32"
> +#else
> +#define CACHE_ARCH "x86_64"
> +#endif
> +#elif defined(__i386__)
> +#define CACHE_ARCH "i386"
> +#else
> +#define CACHE_ARCH "unknown_arch"
> +#endif

This seems incomplete. How about using uname(2)'s machine value? (Will
need a bit of plumbing to detect whether uname is available in libc.)

> +
>  /* 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)
>
>  struct disk_cache {
> @@ -170,20 +182,29 @@ remove_old_cache_directories(void *mem_ctx, char *path, const char *timestamp)
>  }
>
>  static char *
>  create_mesa_cache_dir(void *mem_ctx, char *path, const char *timestamp,
>                        const char *gpu_name)
>  {
>     char *new_path = concatenate_and_mkdir(mem_ctx, path, "mesa");
>     if (new_path == NULL)
>        return NULL;
>
> +   /* Create a parent architecture directory so that we don't remove cache
> +    * files for other architectures. In theory we could share the cache
> +    * between architectures but we have no way of knowing if they were created
> +    * by a compatible Mesa version.
> +    */
> +   new_path = concatenate_and_mkdir(mem_ctx, new_path, CACHE_ARCH);
> +   if (new_path == NULL)
> +      return NULL;
> +
>     /* Remove cache directories for old Mesa versions */
>     remove_old_cache_directories(mem_ctx, new_path, timestamp);
>
>     new_path = concatenate_and_mkdir(mem_ctx, new_path, timestamp);
>     if (new_path == NULL)
>        return NULL;
>
>     new_path = concatenate_and_mkdir(mem_ctx, new_path, gpu_name);
>     if (new_path == NULL)
>        return NULL;
> --
> 2.9.3
>
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