[PATCH 3/3] drm/amdkfd: Split giant svm range

[Philip Yang]

Giant svm range split to smaller ranges, align the range start address
to max svm range pages to improve MMU TLB usage.

Signed-off-by: Philip Yang <philip.y...@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 52 +++++++++++++++++++---------
 1 file changed, 36 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index cf9565ddddf8..044bb99f88ea 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1885,6 +1885,37 @@ __init void svm_range_set_max_pages(struct amdgpu_device 
*adev)
        max_svm_range_pages = ALIGN(max_svm_range_pages, 1ULL << 9);
 }
 
+static int
+__svm_range_add(struct svm_range_list *svms, uint64_t start, uint64_t last,
+              struct list_head *insert_list, struct list_head *update_list)
+{
+       struct svm_range *prange;
+       uint64_t l;
+
+       pr_debug("max_svm_range_pages 0x%llx adding [0x%llx 0x%llx]\n",
+                max_svm_range_pages, start, last);
+
+       while (last >= start) {
+               if (last - start + 1 > max_svm_range_pages) {
+                       if (start % max_svm_range_pages)
+                               l = ALIGN(start, max_svm_range_pages) - 1;
+                       else
+                               l = start + max_svm_range_pages - 1;
+               } else {
+                       l = last;
+               }
+
+               prange = svm_range_new(svms, start, l);
+               if (!prange)
+                       return -ENOMEM;
+               list_add(&prange->list, insert_list);
+               list_add(&prange->update_list, update_list);
+
+               start = l + 1;
+       }
+       return 0;
+}
+
 /**
  * svm_range_add - add svm range and handle overlap
  * @p: the range add to this process svms
@@ -1987,14 +2018,10 @@ svm_range_add(struct kfd_process *p, uint64_t start, 
uint64_t size,
 
                /* insert a new node if needed */
                if (node->start > start) {
-                       prange = svm_range_new(svms, start, node->start - 1);
-                       if (!prange) {
-                               r = -ENOMEM;
+                       r = __svm_range_add(svms, start, node->start - 1,
+                                           insert_list, update_list);
+                       if (r)
                                goto out;
-                       }
-
-                       list_add(&prange->list, insert_list);
-                       list_add(&prange->update_list, update_list);
                }
 
                node = next;
@@ -2002,15 +2029,8 @@ svm_range_add(struct kfd_process *p, uint64_t start, 
uint64_t size,
        }
 
        /* add a final range at the end if needed */
-       if (start <= last) {
-               prange = svm_range_new(svms, start, last);
-               if (!prange) {
-                       r = -ENOMEM;
-                       goto out;
-               }
-               list_add(&prange->list, insert_list);
-               list_add(&prange->update_list, update_list);
-       }
+       if (start <= last)
+               r = __svm_range_add(svms, start, last, insert_list, 
update_list);
 
 out:
        if (r)
-- 
2.35.1