On 03/04/2019 02:46, Lucas De Marchi wrote:
No reason to stick to u32 for platform mask if we can just use more bits
on 64 bit platforms.

$ size drivers/gpu/drm/i915/i915.ko*
    text           data     bss     dec     hex filename
1884779   41334    5408 1931521  1d7901 drivers/gpu/drm/i915/i915.ko
1886693   41358    5408 1933459  1d8093 drivers/gpu/drm/i915/i915.ko.old

How did you get such a large difference, and decrease even? Could you check in the code what is happening? Because I get an increase with this patch:

   text    data     bss     dec     hex filename
1905314   43903    7424 1956641  1ddb21 i915.ko.orig
1905796   43903    7424 1957123  1ddd03 i915.ko.patch

Regards,

Tvrtko


Now on 64 bits we have only one long as opposed to 2 u32:

$ pahole -C intel_runtime_info drivers/gpu/drm/i915/i915.ko
struct intel_runtime_info {
        long unsigned int          platform_mask[1];     /*     0     8 */
...
}

On 32 bits we still have the same thing as before:
$ size drivers/gpu/drm/i915/i915.ko*
    text           data     bss     dec     hex filename
1489839   32485    2816 1525140  174594 drivers/gpu/drm/i915/i915.ko
1489839   32485    2816 1525140  174594 drivers/gpu/drm/i915/i915.ko.old

Besides reducing the code on x86-64 now the array size is automatically
calculated and we don't have to worry about extending it anymore.

v2: fix sparse and checkpatch warnings

Signed-off-by: Lucas De Marchi <[email protected]>
---
  drivers/gpu/drm/i915/i915_drv.h          | 6 +-----
  drivers/gpu/drm/i915/intel_device_info.h | 7 +++----
  2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 0ab4826921f7..9fe765ffe878 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2309,10 +2309,6 @@ __platform_mask_index(const struct intel_runtime_info 
*info,
        const unsigned int pbits =
                BITS_PER_TYPE(info->platform_mask[0]) - INTEL_SUBPLATFORM_BITS;
- /* Expand the platform_mask array if this fails. */
-       BUILD_BUG_ON(INTEL_MAX_PLATFORMS >
-                    pbits * ARRAY_SIZE(info->platform_mask));
-
        return p / pbits;
  }
@@ -2354,7 +2350,7 @@ IS_SUBPLATFORM(const struct drm_i915_private *i915,
        const unsigned int pi = __platform_mask_index(info, p);
        const unsigned int pb = __platform_mask_bit(info, p);
        const unsigned int msb = BITS_PER_TYPE(info->platform_mask[0]) - 1;
-       const u32 mask = info->platform_mask[pi];
+       const unsigned long mask = info->platform_mask[pi];
BUILD_BUG_ON(!__builtin_constant_p(p));
        BUILD_BUG_ON(!__builtin_constant_p(s));
diff --git a/drivers/gpu/drm/i915/intel_device_info.h 
b/drivers/gpu/drm/i915/intel_device_info.h
index 0e579f158016..2f5ca2b6f094 100644
--- a/drivers/gpu/drm/i915/intel_device_info.h
+++ b/drivers/gpu/drm/i915/intel_device_info.h
@@ -214,11 +214,10 @@ struct intel_runtime_info {
         * Platform mask is used for optimizing or-ed IS_PLATFORM calls into
         * into single runtime conditionals, and also to provide groundwork
         * for future per platform, or per SKU build optimizations.
-        *
-        * Array can be extended when necessary if the corresponding
-        * BUILD_BUG_ON is hit.
         */
-       u32 platform_mask[2];
+       unsigned long platform_mask[DIV_ROUND_UP(INTEL_MAX_PLATFORMS,
+                                                BITS_PER_TYPE(unsigned long)
+                                                - INTEL_SUBPLATFORM_BITS)];
u16 device_id;

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