gpu: nvgpu: clear vidmem buffers in worker

We clear buffers allocated in vidmem in buffer free path.
But to clear buffers, we need to submit CE jobs and this
could cause issues/races if free called from critical
path

Hence solve this by moving buffer clear/free to a worker

gk20a_gmmu_free_attr_vid() will now just put mem_desc into
a list and schedule a worker
And worker thread will traverse the list and clear/free
the allocations

In struct gk20a_vidmem_buf, mem variable is statically
allocated. But since we delay free of mem, convert this
variable into a pointer and allocate it dynamically

Since we delay free of vidmem memory, it is now possible
to face OOM conditions during allocations. Hence while
allocating block until we have sufficient memory
available with an upper limit of 1S

Jira DNVGPU-84

Change-Id: I7925590644afae50b6fc04c6e1e43bbaa1c220fd
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/1201346
(cherry picked from commit b4dec4a30de2431369d677acca00e420f8e581a5)
Reviewed-on: http://git-master/r/1210950
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
index c6360955..54d3dfd0 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
@@ -71,6 +71,7 @@ struct mem_desc {
         size_t size;
         u64 gpu_va;
         bool fixed; /* vidmem only */
+        struct list_head clear_list_entry; /* vidmem only */
 };
 
 struct mem_desc_sub {
@@ -414,7 +415,11 @@ struct mm_gk20a {
 
                 u32 ce_ctx_id;
                 bool cleared;
+
+                struct list_head clear_list_head;
+                struct mutex clear_list_mutex;
         } vidmem;
+        struct work_struct vidmem_clear_mem_worker;
 };
 
 int gk20a_mm_init(struct mm_gk20a *mm);