there is a scheduling balance issue about get node like:
a. process A allocates full memory and use it for submission.
b. process B tries to allocates memory, will wait for process A BO idle in 
eviction.
c. process A completes the job, process B eviction will put process A BO node,
but in the meantime, process C is comming to allocate BO, whill directly get 
node successfully, and do submission,
process B will again wait for process C BO idle.
d. repeat the above setps, process B could be delayed much more.

later allocation must not be ahead of front in same place.

Change-Id: I3daa892e50f82226c552cc008a29e55894a98f18
Signed-off-by: Chunming Zhou <david1.z...@amd.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c    | 69 +++++++++++++++++++++++++++++++++++++++--
 include/drm/ttm/ttm_bo_api.h    |  7 +++++
 include/drm/ttm/ttm_bo_driver.h |  7 +++++
 3 files changed, 80 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index d33a6bb742a1..558ec2cf465d 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -841,6 +841,58 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object 
*bo,
        return 0;
 }
 
+static void ttm_man_init_waiter(struct ttm_bo_waiter *waiter,
+                               struct ttm_buffer_object *bo,
+                               const struct ttm_place *place)
+{
+       waiter->tbo = bo;
+       memcpy((void *)&waiter->place, (void *)place, sizeof(*place));
+       INIT_LIST_HEAD(&waiter->list);
+}
+
+static void ttm_man_add_waiter(struct ttm_mem_type_manager *man,
+                              struct ttm_bo_waiter *waiter)
+{
+       if (!waiter)
+               return;
+       spin_lock(&man->wait_lock);
+       list_add_tail(&waiter->list, &man->waiter_list);
+       spin_unlock(&man->wait_lock);
+}
+
+static void ttm_man_del_waiter(struct ttm_mem_type_manager *man,
+                              struct ttm_bo_waiter *waiter)
+{
+       if (!waiter)
+               return;
+       spin_lock(&man->wait_lock);
+       if (!list_empty(&waiter->list))
+               list_del(&waiter->list);
+       spin_unlock(&man->wait_lock);
+       kfree(waiter);
+}
+
+int ttm_man_check_bo(struct ttm_mem_type_manager *man,
+                    struct ttm_buffer_object *bo,
+                    const struct ttm_place *place)
+{
+       struct ttm_bo_waiter *waiter, *tmp;
+
+       spin_lock(&man->wait_lock);
+       list_for_each_entry_safe(waiter, tmp, &man->waiter_list, list) {
+               if ((bo != waiter->tbo) &&
+                   ((place->fpfn >= waiter->place.fpfn &&
+                     place->fpfn <= waiter->place.lpfn) ||
+                    (place->lpfn <= waiter->place.lpfn && place->lpfn >=
+                     waiter->place.fpfn)))
+                   goto later_bo;
+       }
+       spin_unlock(&man->wait_lock);
+       return true;
+later_bo:
+       spin_unlock(&man->wait_lock);
+       return false;
+}
 /**
  * Repeatedly evict memory from the LRU for @mem_type until we create enough
  * space, or we've evicted everything and there isn't enough space.
@@ -853,17 +905,26 @@ static int ttm_bo_mem_force_space(struct 
ttm_buffer_object *bo,
 {
        struct ttm_bo_device *bdev = bo->bdev;
        struct ttm_mem_type_manager *man = &bdev->man[mem_type];
+       struct ttm_bo_waiter waiter;
        int ret;
 
+       ttm_man_init_waiter(&waiter, bo, place);
+       ttm_man_add_waiter(man, &waiter);
        do {
                ret = (*man->func->get_node)(man, bo, place, mem);
-               if (unlikely(ret != 0))
+               if (unlikely(ret != 0)) {
+                       ttm_man_del_waiter(man, &waiter);
                        return ret;
-               if (mem->mm_node)
+               }
+               if (mem->mm_node) {
+                       ttm_man_del_waiter(man, &waiter);
                        break;
+               }
                ret = ttm_mem_evict_first(bdev, mem_type, place, ctx);
-               if (unlikely(ret != 0))
+               if (unlikely(ret != 0)) {
+                       ttm_man_del_waiter(man, &waiter);
                        return ret;
+               }
        } while (1);
        mem->mem_type = mem_type;
        return ttm_bo_add_move_fence(bo, man, mem);
@@ -1450,6 +1511,8 @@ int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned 
type,
        man->use_io_reserve_lru = false;
        mutex_init(&man->io_reserve_mutex);
        spin_lock_init(&man->move_lock);
+       spin_lock_init(&man->wait_lock);
+       INIT_LIST_HEAD(&man->waiter_list);
        INIT_LIST_HEAD(&man->io_reserve_lru);
 
        ret = bdev->driver->init_mem_type(bdev, type, man);
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 2cd025c2abe7..0fce4dbd02e7 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -40,6 +40,7 @@
 #include <linux/mm.h>
 #include <linux/bitmap.h>
 #include <linux/reservation.h>
+#include <drm/ttm/ttm_placement.h>
 
 struct ttm_bo_device;
 
@@ -232,6 +233,12 @@ struct ttm_buffer_object {
        struct mutex wu_mutex;
 };
 
+struct ttm_bo_waiter {
+       struct ttm_buffer_object *tbo;
+       struct ttm_place place;
+       struct list_head list;
+};
+
 /**
  * struct ttm_bo_kmap_obj
  *
diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index 9b417eb2df20..dc6b8b4c9e06 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -293,6 +293,10 @@ struct ttm_mem_type_manager {
        bool io_reserve_fastpath;
        spinlock_t move_lock;
 
+       /* waiters in list */
+       spinlock_t wait_lock;
+       struct list_head waiter_list;
+
        /*
         * Protected by @io_reserve_mutex:
         */
@@ -748,6 +752,9 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
                     struct ttm_mem_reg *mem,
                     struct ttm_operation_ctx *ctx);
 
+int ttm_man_check_bo(struct ttm_mem_type_manager *man,
+                    struct ttm_buffer_object *bo,
+                    const struct ttm_place *place);
 void ttm_bo_mem_put(struct ttm_buffer_object *bo, struct ttm_mem_reg *mem);
 void ttm_bo_mem_put_locked(struct ttm_buffer_object *bo,
                           struct ttm_mem_reg *mem);
-- 
2.14.1

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