drm/radeon: let sa manager block for fences to wait for v2

Otherwise we can encounter out of memory situations under extreme load.

v2: add documentation for the new function

Signed-off-by: Christian König <deathsimple@vodafone.de>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 60 insertions, 22 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_sa.c b/drivers/gpu/drm/radeon/radeon_sa.c
index 81dbb5b946ef..4e771240fdd0 100644
--- a/drivers/gpu/drm/radeon/radeon_sa.c
+++ b/drivers/gpu/drm/radeon/radeon_sa.c
@@ -54,7 +54,7 @@ int radeon_sa_bo_manager_init(struct radeon_device *rdev,
 {
         int i, r;
 
-        spin_lock_init(&sa_manager->lock);
+        init_waitqueue_head(&sa_manager->wq);
         sa_manager->bo = NULL;
         sa_manager->size = size;
         sa_manager->domain = domain;
@@ -211,6 +211,39 @@ static bool radeon_sa_bo_try_alloc(struct radeon_sa_manager *sa_manager,
         return false;
 }
 
+/**
+ * radeon_sa_event - Check if we can stop waiting
+ *
+ * @sa_manager: pointer to the sa_manager
+ * @size: number of bytes we want to allocate
+ * @align: alignment we need to match
+ *
+ * Check if either there is a fence we can wait for or
+ * enough free memory to satisfy the allocation directly
+ */
+static bool radeon_sa_event(struct radeon_sa_manager *sa_manager,
+                            unsigned size, unsigned align)
+{
+        unsigned soffset, eoffset, wasted;
+        int i;
+
+        for (i = 0; i < RADEON_NUM_RINGS; ++i) {
+                if (!list_empty(&sa_manager->flist[i])) {
+                        return true;
+                }
+        }
+
+        soffset = radeon_sa_bo_hole_soffset(sa_manager);
+        eoffset = radeon_sa_bo_hole_eoffset(sa_manager);
+        wasted = (align - (soffset % align)) % align;
+
+        if ((eoffset - soffset) >= (size + wasted)) {
+                return true;
+        }
+
+        return false;
+}
+
 static bool radeon_sa_bo_next_hole(struct radeon_sa_manager *sa_manager,
                                    struct radeon_fence **fences,
                                    unsigned *tries)
@@ -297,8 +330,8 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
         INIT_LIST_HEAD(&(*sa_bo)->olist);
         INIT_LIST_HEAD(&(*sa_bo)->flist);
 
-        spin_lock(&sa_manager->lock);
-        do {
+        spin_lock(&sa_manager->wq.lock);
+        while(1) {
                 for (i = 0; i < RADEON_NUM_RINGS; ++i) {
                         fences[i] = NULL;
                         tries[i] = 0;
@@ -309,30 +342,34 @@ int radeon_sa_bo_new(struct radeon_device *rdev,
 
                         if (radeon_sa_bo_try_alloc(sa_manager, *sa_bo,
                                                    size, align)) {
-                                spin_unlock(&sa_manager->lock);
+                                spin_unlock(&sa_manager->wq.lock);
                                 return 0;
                         }
 
                         /* see if we can skip over some allocations */
                 } while (radeon_sa_bo_next_hole(sa_manager, fences, tries));
 
-                if (block) {
-                        spin_unlock(&sa_manager->lock);
-                        r = radeon_fence_wait_any(rdev, fences, false);
-                        spin_lock(&sa_manager->lock);
-                        if (r) {
-                                /* if we have nothing to wait for we
-                                   are practically out of memory */
-                                if (r == -ENOENT) {
-                                        r = -ENOMEM;
-                                }
-                                goto out_err;
-                        }
+                if (!block) {
+                        break;
+                }
+
+                spin_unlock(&sa_manager->wq.lock);
+                r = radeon_fence_wait_any(rdev, fences, false);
+                spin_lock(&sa_manager->wq.lock);
+                /* if we have nothing to wait for block */
+                if (r == -ENOENT) {
+                        r = wait_event_interruptible_locked(
+                                sa_manager->wq, 
+                                radeon_sa_event(sa_manager, size, align)
+                        );
+                }
+                if (r) {
+                        goto out_err;
                 }
-        } while (block);
+        };
 
 out_err:
-        spin_unlock(&sa_manager->lock);
+        spin_unlock(&sa_manager->wq.lock);
         kfree(*sa_bo);
         *sa_bo = NULL;
         return r;
@@ -348,7 +385,7 @@ void radeon_sa_bo_free(struct radeon_device *rdev, struct radeon_sa_bo **sa_bo,
         }
 
         sa_manager = (*sa_bo)->manager;
-        spin_lock(&sa_manager->lock);
+        spin_lock(&sa_manager->wq.lock);
         if (fence && !radeon_fence_signaled(fence)) {
                 (*sa_bo)->fence = radeon_fence_ref(fence);
                 list_add_tail(&(*sa_bo)->flist,
@@ -356,7 +393,8 @@ void radeon_sa_bo_free(struct radeon_device *rdev, struct radeon_sa_bo **sa_bo,
         } else {
                 radeon_sa_bo_remove_locked(*sa_bo);
         }
-        spin_unlock(&sa_manager->lock);
+        wake_up_all_locked(&sa_manager->wq);
+        spin_unlock(&sa_manager->wq.lock);
         *sa_bo = NULL;
 }
 
@@ -366,7 +404,7 @@ void radeon_sa_bo_dump_debug_info(struct radeon_sa_manager *sa_manager,
 {
         struct radeon_sa_bo *i;
 
-        spin_lock(&sa_manager->lock);
+        spin_lock(&sa_manager->wq.lock);
         list_for_each_entry(i, &sa_manager->olist, olist) {
                 if (&i->olist == sa_manager->hole) {
                         seq_printf(m, ">");
@@ -381,6 +419,6 @@ void radeon_sa_bo_dump_debug_info(struct radeon_sa_manager *sa_manager,
                 }
                 seq_printf(m, "\n");
         }
-        spin_unlock(&sa_manager->lock);
+        spin_unlock(&sa_manager->wq.lock);
 }
 #endif