[Mesa-dev] [PATCH] i965: free scratch buffers when destroying the context

[Jordan Justen]

Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>

On 2015-03-06 00:26:35, Iago Toral Quiroga wrote:
> If scratch space is needed for a shader stage we try to reuse the last scratch
> buffer bound to that stage. If we can't, we free the old scratch buffer and
> allocate a new one. This means we always keep the last scratch buffer for a
> particular shader stage around for the entire life span of the context.
> 
> These buffers are being reported by Valgrind as definitely lost after
> destroying the OpenGL context. For example, for the geometry shader stage:
> 
> ==18350== 248 bytes in 1 blocks are definitely lost in loss record 85 of 150
> ==18350==    at 0x4C2CC70: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
> ==18350==    by 0xA1B35D6: drm_intel_gem_bo_alloc_internal (intel_bufmgr_gem.c:724)
> ==18350==    by 0xA1B383F: drm_intel_gem_bo_alloc (intel_bufmgr_gem.c:794)
> ==18350==    by 0xA1AEFA3: drm_intel_bo_alloc (intel_bufmgr.c:52)
> ==18350==    by 0x9D08E31: brw_get_scratch_bo (brw_program.c:226)
> ==18350==    by 0x9D2A0F2: do_gs_prog (brw_vec4_gs.c:280)
> ==18350==    by 0x9D2A635: brw_gs_precompile (brw_vec4_gs.c:401)
> ==18350==    by 0x9D14F68: brw_shader_precompile(gl_context*, gl_shader_program*) (brw_shader.cpp:76)
> ==18350==    by 0x9D157B8: brw_link_shader (brw_shader.cpp:269)
> ==18350==    by 0x9B0941E: _mesa_glsl_link_shader (ir_to_mesa.cpp:3038)
> ==18350==    by 0x99AE4ED: link_program (shaderapi.c:917)
> ==18350==    by 0x99AF365: _mesa_LinkProgram (shaderapi.c:1385)
> 
> So make sure that by the time we destroy the context we check if we have live
> scratch buffers for the various stages and release them if that is the case.
> ---
> I sent this some months ago but I think it was never reviewed. The problems
> still exists and it is easy to spot by using geometry shaders in SNB, which
> always require scratch space due to the use of a register array to buffer
> vertex data.
> 
>  src/mesa/drivers/dri/i965/brw_context.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
> index 786e6f5..972e458 100644
> --- a/src/mesa/drivers/dri/i965/brw_context.c
> +++ b/src/mesa/drivers/dri/i965/brw_context.c
> @@ -908,6 +908,12 @@ intelDestroyContext(__DRIcontext * driContextPriv)
>     brw_draw_destroy(brw);
>  
>     drm_intel_bo_unreference(brw->curbe.curbe_bo);
> +   if (brw->vs.base.scratch_bo)
> +      drm_intel_bo_unreference(brw->vs.base.scratch_bo);
> +   if (brw->gs.base.scratch_bo)
> +      drm_intel_bo_unreference(brw->gs.base.scratch_bo);
> +   if (brw->wm.base.scratch_bo)
> +      drm_intel_bo_unreference(brw->wm.base.scratch_bo);
>  
>     drm_intel_gem_context_destroy(brw->hw_ctx);
>  
> -- 
> 1.9.1
> 
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