Hi Thomas,

actually I was very happy to get rid of that stuff.

In the long run I indeed wanted to replace ctx->resv with the ww_acquire_ctx to enable eviction of even more things, but that is a different story.

Recursive locking is usually something we should try to avoid.

Regards,
Christian.

Am 15.12.2017 um 08:01 schrieb Thomas Hellstrom:
Roger and Chrisitian,

Correct me if I'm wrong, but It seems to me like a lot of the recent changes to ttm_bo.c are to allow recursive reservation object locking in the case of shared reservation objects, but only in certain functions and with special arguments so it doesn't look like recursive locking to the lockdep checker.  Wouldn't it be a lot cleaner if we were to hide all this in a resurrected __ttm_bo_reserve something along the lines of

int __ttm_bo_reserve(struct ttm_bo *bo, struct ttm_operation_ctx *ctx) {
    if (ctx && ctx->resv == bo->resv) {
#ifdef CONFIG_LOCKDEP
        WARN_ON(bo->reserved);
lockdep_assert_held(&ctx->resv);
        ctx->reserve_count++;
bo->reserved = true;
#endif
        return0;
     } else {
        int ret = reservation_object_lock(bo->resv, NULL) ? 0:-EBUSY;

        if (ret)
            return ret;
#ifdef CONFIG_LOCKDEP
        WARN_ON(bo->reserved);
        bo->reserved = true;
#endif
        return 0;
}

And similar for tryreserve and unreserve? Perhaps with a ww_acquire_ctx included somewhere as well...

/Thomas




On 12/14/2017 09:10 AM, Roger He wrote:
Change-Id: I0c6ece0decd18d30ccc94e5c7ca106d351941c62
Signed-off-by: Roger He <hongbo...@amd.com>
---
  drivers/gpu/drm/ttm/ttm_bo.c | 11 +++++------
  1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 098b22e..ba5b486 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -707,7 +707,6 @@ bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo,
  EXPORT_SYMBOL(ttm_bo_eviction_valuable);
    static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
-                   struct reservation_object *resv,
                     uint32_t mem_type,
                     const struct ttm_place *place,
                     struct ttm_operation_ctx *ctx)
@@ -722,8 +721,9 @@ static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
      spin_lock(&glob->lru_lock);
      for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
          list_for_each_entry(bo, &man->lru[i], lru) {
-            if (bo->resv == resv) {
-                if (list_empty(&bo->ddestroy))
+            if (bo->resv == ctx->resv) {
+                if (!ctx->allow_reserved_eviction &&
+                    list_empty(&bo->ddestroy))
                      continue;
              } else {
                  locked = reservation_object_trylock(bo->resv);
@@ -835,7 +835,7 @@ static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
              return ret;
          if (mem->mm_node)
              break;
-        ret = ttm_mem_evict_first(bdev, bo->resv, mem_type, place, ctx);
+        ret = ttm_mem_evict_first(bdev, mem_type, place, ctx);
          if (unlikely(ret != 0))
              return ret;
      } while (1);
@@ -1332,8 +1332,7 @@ static int ttm_bo_force_list_clean(struct ttm_bo_device *bdev,
      for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
          while (!list_empty(&man->lru[i])) {
              spin_unlock(&glob->lru_lock);
-            ret = ttm_mem_evict_first(bdev, NULL, mem_type,
-                          NULL, &ctx);
+            ret = ttm_mem_evict_first(bdev, mem_type, NULL, &ctx);
              if (ret)
                  return ret;
              spin_lock(&glob->lru_lock);



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