[PATCH v2 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 | 49 +++++++++++++++++++---------
 1 file changed, 33 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 098060147de6..6529a40fb508 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1889,6 +1889,31 @@ void svm_range_set_max_pages(struct amdgpu_device *adev)
        WRITE_ONCE(max_svm_range_pages, max_pages);
 }
 
+static int
+svm_range_split_new(struct svm_range_list *svms, uint64_t start, uint64_t last,
+                   uint64_t max_pages, 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_pages, start, last);
+
+       while (last >= start) {
+               l = min(last, ALIGN_DOWN(start + max_pages, max_pages) - 1);
+
+               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
@@ -1991,14 +2016,11 @@ 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_split_new(svms, start, node->start - 1,
+                                               READ_ONCE(max_svm_range_pages),
+                                               insert_list, update_list);
+                       if (r)
                                goto out;
-                       }
-
-                       list_add(&prange->list, insert_list);
-                       list_add(&prange->update_list, update_list);
                }
 
                node = next;
@@ -2006,15 +2028,10 @@ 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_split_new(svms, start, last,
+                                       READ_ONCE(max_svm_range_pages),
+                                       insert_list, update_list);
 
 out:
        if (r)
-- 
2.35.1