intel: Evict cached VMA in order to make room for new mappings

As the max number of VMA mappings is a hard per-process limit, we need
to include the number of currently active mappings when evicting in
order to make room for a new mmap.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/intel/intel_bufmgr_gem.c b/intel/intel_bufmgr_gem.c
index c535dee..55ff5ab 100644 (file)
--- a/intel/intel_bufmgr_gem.c
+++ b/intel/intel_bufmgr_gem.c
@@ -98,7 +98,7 @@ typedef struct _drm_intel_bufmgr_gem {
 
        drmMMListHead named;
        drmMMListHead vma_cache;
-       int vma_count, vma_max;
+       int vma_count, vma_open, vma_max;
 
        uint64_t gtt_size;
        int available_fences;
@@ -938,13 +938,20 @@ drm_intel_gem_cleanup_bo_cache(drm_intel_bufmgr_gem *bufmgr_gem, time_t time)
 
 static void drm_intel_gem_bo_purge_vma_cache(drm_intel_bufmgr_gem *bufmgr_gem)
 {
-       DBG("%s: count=%d, limit=%d\n", __FUNCTION__,
-           bufmgr_gem->vma_count, bufmgr_gem->vma_max);
+       int limit;
+
+       DBG("%s: cached=%d, open=%d, limit=%d\n", __FUNCTION__,
+           bufmgr_gem->vma_count, bufmgr_gem->vma_open, bufmgr_gem->vma_max);
 
        if (bufmgr_gem->vma_max < 0)
                return;
 
-       while (bufmgr_gem->vma_count > bufmgr_gem->vma_max) {
+       /* We may need to evict a few entries in order to create new mmaps */
+       limit = bufmgr_gem->vma_max - 2*bufmgr_gem->vma_open;
+       if (limit < 0)
+               limit = 0;
+
+       while (bufmgr_gem->vma_count > limit) {
                drm_intel_bo_gem *bo_gem;
 
                bo_gem = DRMLISTENTRY(drm_intel_bo_gem,
@@ -966,9 +973,10 @@ static void drm_intel_gem_bo_purge_vma_cache(drm_intel_bufmgr_gem *bufmgr_gem)
        }
 }
 
-static void drm_intel_gem_bo_add_to_vma_cache(drm_intel_bufmgr_gem *bufmgr_gem,
-                                             drm_intel_bo_gem *bo_gem)
+static void drm_intel_gem_bo_close_vma(drm_intel_bufmgr_gem *bufmgr_gem,
+                                      drm_intel_bo_gem *bo_gem)
 {
+       bufmgr_gem->vma_open--;
        DRMLISTADDTAIL(&bo_gem->vma_list, &bufmgr_gem->vma_cache);
        if (bo_gem->mem_virtual)
                bufmgr_gem->vma_count++;
@@ -977,14 +985,16 @@ static void drm_intel_gem_bo_add_to_vma_cache(drm_intel_bufmgr_gem *bufmgr_gem,
        drm_intel_gem_bo_purge_vma_cache(bufmgr_gem);
 }
 
-static void drm_intel_gem_bo_remove_from_vma_cache(drm_intel_bufmgr_gem *bufmgr_gem,
-                                                  drm_intel_bo_gem *bo_gem)
+static void drm_intel_gem_bo_open_vma(drm_intel_bufmgr_gem *bufmgr_gem,
+                                     drm_intel_bo_gem *bo_gem)
 {
+       bufmgr_gem->vma_open++;
        DRMLISTDEL(&bo_gem->vma_list);
        if (bo_gem->mem_virtual)
                bufmgr_gem->vma_count--;
        if (bo_gem->gtt_virtual)
                bufmgr_gem->vma_count--;
+       drm_intel_gem_bo_purge_vma_cache(bufmgr_gem);
 }
 
 static void
@@ -1023,6 +1033,7 @@ drm_intel_gem_bo_unreference_final(drm_intel_bo *bo, time_t time)
        if (bo_gem->map_count) {
                DBG("bo freed with non-zero map-count %d\n", bo_gem->map_count);
                bo_gem->map_count = 0;
+               drm_intel_gem_bo_close_vma(bufmgr_gem, bo_gem);
        }
 
        DRMLISTDEL(&bo_gem->name_list);
@@ -1037,9 +1048,6 @@ drm_intel_gem_bo_unreference_final(drm_intel_bo *bo, time_t time)
                bo_gem->name = NULL;
                bo_gem->validate_index = -1;
 
-               if (bo_gem->mem_virtual || bo_gem->gtt_virtual)
-                       drm_intel_gem_bo_add_to_vma_cache(bufmgr_gem, bo_gem);
-
                DRMLISTADDTAIL(&bo_gem->head, &bucket->head);
        } else {
                drm_intel_gem_bo_free(bo);
@@ -1085,7 +1093,7 @@ static int drm_intel_gem_bo_map(drm_intel_bo *bo, int write_enable)
        pthread_mutex_lock(&bufmgr_gem->lock);
 
        if (bo_gem->map_count++ == 0)
-               drm_intel_gem_bo_remove_from_vma_cache(bufmgr_gem, bo_gem);
+               drm_intel_gem_bo_open_vma(bufmgr_gem, bo_gem);
 
        if (!bo_gem->mem_virtual) {
                struct drm_i915_gem_mmap mmap_arg;
@@ -1106,7 +1114,7 @@ static int drm_intel_gem_bo_map(drm_intel_bo *bo, int write_enable)
                            __FILE__, __LINE__, bo_gem->gem_handle,
                            bo_gem->name, strerror(errno));
                        if (--bo_gem->map_count == 0)
-                               drm_intel_gem_bo_add_to_vma_cache(bufmgr_gem, bo_gem);
+                               drm_intel_gem_bo_close_vma(bufmgr_gem, bo_gem);
                        pthread_mutex_unlock(&bufmgr_gem->lock);
                        return ret;
                }
@@ -1149,7 +1157,7 @@ int drm_intel_gem_bo_map_gtt(drm_intel_bo *bo)
        pthread_mutex_lock(&bufmgr_gem->lock);
 
        if (bo_gem->map_count++ == 0)
-               drm_intel_gem_bo_remove_from_vma_cache(bufmgr_gem, bo_gem);
+               drm_intel_gem_bo_open_vma(bufmgr_gem, bo_gem);
 
        /* Get a mapping of the buffer if we haven't before. */
        if (bo_gem->gtt_virtual == NULL) {
@@ -1188,7 +1196,7 @@ int drm_intel_gem_bo_map_gtt(drm_intel_bo *bo)
                            bo_gem->gem_handle, bo_gem->name,
                            strerror(errno));
                        if (--bo_gem->map_count == 0)
-                               drm_intel_gem_bo_add_to_vma_cache(bufmgr_gem, bo_gem);
+                               drm_intel_gem_bo_close_vma(bufmgr_gem, bo_gem);
                        pthread_mutex_unlock(&bufmgr_gem->lock);
                        return ret;
                }
@@ -1251,7 +1259,7 @@ static int drm_intel_gem_bo_unmap(drm_intel_bo *bo)
         * limits and cause later failures.
         */
        if (--bo_gem->map_count == 0) {
-               drm_intel_gem_bo_add_to_vma_cache(bufmgr_gem, bo_gem);
+               drm_intel_gem_bo_close_vma(bufmgr_gem, bo_gem);
                bo->virtual = NULL;
        }
        pthread_mutex_unlock(&bufmgr_gem->lock);