gpu: nvgpu: Do not pre-allocate cmdbuf entries

Do not preallocate cmdbuf tracking entries. Allocate them only when
needed.

Bug 200104160

Change-Id: I12f8392723c301a368af1e280893ff993480477f
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/743953
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/755148

2 files changed, 8 insertions, 43 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index 5a71e874..8ad1dcca 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -1116,8 +1116,7 @@ static int channel_gk20a_alloc_priv_cmdbuf(struct channel_gk20a *c)
         struct device *d = dev_from_gk20a(c->g);
         struct vm_gk20a *ch_vm = c->vm;
         struct priv_cmd_queue *q = &c->priv_cmd_q;
-        struct priv_cmd_entry *e;
-        u32 i = 0, size;
+        u32 size;
         int err = 0;
 
         /* Kernel can insert gpfifos before and after user gpfifos.
@@ -1143,19 +1142,6 @@ static int channel_gk20a_alloc_priv_cmdbuf(struct channel_gk20a *c)
         INIT_LIST_HEAD(&q->head);
         INIT_LIST_HEAD(&q->free);
 
-        /* pre-alloc 25% of priv cmdbuf entries and put them on free list */
-        for (i = 0; i < q->size / 4; i++) {
-                e = kzalloc(sizeof(struct priv_cmd_entry), GFP_KERNEL);
-                if (!e) {
-                        gk20a_err(d, "ch %d: fail to pre-alloc cmd entry",
-                                c->hw_chid);
-                        err = -ENOMEM;
-                        goto clean_up;
-                }
-                e->pre_alloc = true;
-                list_add(&e->list, &q->free);
-        }
-
         return 0;
 
 clean_up:
@@ -1186,8 +1172,7 @@ static void channel_gk20a_free_priv_cmdbuf(struct channel_gk20a *c)
         head = &q->free;
         list_for_each_safe(pos, tmp, head) {
                 e = container_of(pos, struct priv_cmd_entry, list);
-                e->pre_alloc = false;
-                free_priv_cmdbuf(c, e);
+                kfree(e);
         }
 
         memset(q, 0, sizeof(struct priv_cmd_queue));
@@ -1199,7 +1184,6 @@ int gk20a_channel_alloc_priv_cmdbuf(struct channel_gk20a *c, u32 orig_size,
 {
         struct priv_cmd_queue *q = &c->priv_cmd_q;
         struct priv_cmd_entry *e;
-        struct list_head *node;
         u32 free_count;
         u32 size = orig_size;
         bool no_retry = false;
@@ -1228,22 +1212,12 @@ TRY_AGAIN:
                         return -EAGAIN;
         }
 
-        if (unlikely(list_empty(&q->free))) {
-
-                gk20a_dbg_info("ch %d: run out of pre-alloc entries",
+        e = kzalloc(sizeof(struct priv_cmd_entry), GFP_KERNEL);
+        if (!e) {
+                gk20a_err(dev_from_gk20a(c->g),
+                        "ch %d: fail to allocate priv cmd entry",
                         c->hw_chid);
-
-                e = kzalloc(sizeof(struct priv_cmd_entry), GFP_KERNEL);
-                if (!e) {
-                        gk20a_err(dev_from_gk20a(c->g),
-                                "ch %d: fail to allocate priv cmd entry",
-                                c->hw_chid);
-                        return -ENOMEM;
-                }
-        } else  {
-                node = q->free.next;
-                list_del(node);
-                e = container_of(node, struct priv_cmd_entry, list);
+                return -ENOMEM;
         }
 
         e->size = orig_size;
@@ -1281,20 +1255,12 @@ TRY_AGAIN:
 static void free_priv_cmdbuf(struct channel_gk20a *c,
                              struct priv_cmd_entry *e)
 {
-        struct priv_cmd_queue *q = &c->priv_cmd_q;
-
         if (!e)
                 return;
 
         list_del(&e->list);
 
-        if (unlikely(!e->pre_alloc))
-                kfree(e);
-        else {
-                memset(e, 0, sizeof(struct priv_cmd_entry));
-                e->pre_alloc = true;
-                list_add(&e->list, &q->free);
-        }
+        kfree(e);
 }
 
 /* free entries if they're no longer being used */
diff --git a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
index 47ebd2a1..231f7c9a 100644
--- a/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/mm_gk20a.h
@@ -168,7 +168,6 @@ struct priv_cmd_entry {
         u32 gp_get;     /* gp_get when submitting last priv cmd */
         u32 gp_put;     /* gp_put when submitting last priv cmd */
         u32 gp_wrap;    /* wrap when submitting last priv cmd */
-        bool pre_alloc; /* prealloc entry, free to free list */
         struct list_head list;  /* node for lists */
 };