On Fri, Jan 16, 2015 at 05:45:59PM -0800, Kristian Høgsberg wrote:
> In userspace we can track which buffer a relocation refers to in
> constant time. However, the kernel has to look up the per-fd gem
> handle for each relocation. Using the I915_EXEC_HANDLE_LUT flag lets
> us use the the bos validation list index instead of the gem handle in
> the relocation entries. This allows the kernel to look up the bo for
> a reloc in constant time.
^near
> Signed-off-by: Kristian Høgsberg <krh@xxxxxxxxxxxxx>
Ok, I thought libdrm_intel was doing something questionable with its
cache of reloc trees, but that doesn't actually impact the execlist.
With the minor inline comment,
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> ---
> intel/intel_bufmgr_gem.c | 33 +++++++++++++++++++++++++++++++--
> 1 file changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
> @@ -3569,6 +3594,10 @@ drm_intel_bufmgr_gem_init(int fd, int batch_size)
> }
> }
>
> + gp.param = I915_PARAM_HAS_EXEC_HANDLE_LUT;
> + ret = drmIoctl(bufmgr_gem->fd, DRM_IOCTL_I915_GETPARAM, &gp);
> + bufmgr_gem->has_handle_lut = ret == 0;
Better to use
val = 0;
gp.value = &val;
(void)drmIoctl(bufmgr_gem->fd, DRM_IOCTL_I915_GETPARAM, &gp);
bufmgr_gem->has_handle_lut = val > 0;
for future proofing.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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