winsys/svga: Optionally avoid caching buffer maps

Mapping of graphics kernel buffers is quite costly. Therefore the svga
drm winsys caches all kernel buffer maps. However, that may lead to
less testing coverage of the unmap paths and (possibly) processes running
out of virtual memory space. Introduce a possibility to avoid that caching
by setting the environment variable SVGA_FORCE_KERNEL_UNMAPS to 1.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Matthew McClure <mcclurem@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4804>

diff --git a/src/gallium/winsys/svga/drm/vmw_buffer.c b/src/gallium/winsys/svga/drm/vmw_buffer.c
index e2ddf78ed2edfe430dd8ea88bed14ba51f36e6b3..03db92a648159bc342a57299fd17a4933bf56551 100644 (file)
--- a/src/gallium/winsys/svga/drm/vmw_buffer.c
+++ b/src/gallium/winsys/svga/drm/vmw_buffer.c
@@ -63,6 +63,7 @@ struct vmw_gmr_buffer
    struct vmw_region *region;
    void *map;
    unsigned map_flags;
+   unsigned map_count;
 };
 
 
@@ -104,8 +105,12 @@ vmw_gmr_buffer_destroy(struct pb_buffer *_buf)
 {
    struct vmw_gmr_buffer *buf = vmw_gmr_buffer(_buf);
 
-   vmw_ioctl_region_unmap(buf->region);
-   
+   assert(buf->map_count == 0);
+   if (buf->map) {
+      assert(buf->mgr->vws->cache_maps);
+      vmw_ioctl_region_unmap(buf->region);
+   }
+
    vmw_ioctl_region_destroy(buf->region);
 
    FREE(buf);
@@ -126,7 +131,6 @@ vmw_gmr_buffer_map(struct pb_buffer *_buf,
    if (!buf->map)
       return NULL;
 
-
    if ((_buf->usage & VMW_BUFFER_USAGE_SYNC) &&
        !(flags & PB_USAGE_UNSYNCHRONIZED)) {
       ret = vmw_ioctl_syncforcpu(buf->region,
@@ -137,6 +141,7 @@ vmw_gmr_buffer_map(struct pb_buffer *_buf,
          return NULL;
    }
 
+   buf->map_count++;
    return buf->map;
 }
 
@@ -153,6 +158,12 @@ vmw_gmr_buffer_unmap(struct pb_buffer *_buf)
                                !(flags & PB_USAGE_CPU_WRITE),
                                FALSE);
    }
+
+   assert(buf->map_count > 0);
+   if (!--buf->map_count && !buf->mgr->vws->cache_maps) {
+      vmw_ioctl_region_unmap(buf->region);
+      buf->map = NULL;
+   }
 }
 
 

diff --git a/src/gallium/winsys/svga/drm/vmw_screen.c b/src/gallium/winsys/svga/drm/vmw_screen.c
index 8b4b89981b20d35f24da01d27fc8c7f3455316ac..2f70212de616c556b99e888e2d4fc58065b4ac89 100644 (file)
--- a/src/gallium/winsys/svga/drm/vmw_screen.c
+++ b/src/gallium/winsys/svga/drm/vmw_screen.c
@@ -67,6 +67,7 @@ vmw_winsys_create( int fd )
 {
    struct vmw_winsys_screen *vws;
    struct stat stat_buf;
+   const char *getenv_val;
 
    if (dev_hash == NULL) {
       dev_hash = _mesa_hash_table_create(NULL, vmw_dev_hash, vmw_dev_compare);
@@ -97,6 +98,8 @@ vmw_winsys_create( int fd )
    vws->base.have_gb_dma = !vws->force_coherent;
    vws->base.need_to_rebind_resources = FALSE;
    vws->base.have_transfer_from_buffer_cmd = vws->base.have_vgpu10;
+   getenv_val = getenv("SVGA_FORCE_KERNEL_UNMAPS");
+   vws->cache_maps = !getenv_val || strcmp(getenv_val, "0") == 0;
    vws->fence_ops = vmw_fence_ops_create(vws);
    if (!vws->fence_ops)
       goto out_no_fence_ops;

diff --git a/src/gallium/winsys/svga/drm/vmw_screen.h b/src/gallium/winsys/svga/drm/vmw_screen.h
index c55de4a2b6fb4a79d096795962a81447424a8dac..4cf6b3fd8950ccabfb51c4e9ac2a407d2efa075c 100644 (file)
--- a/src/gallium/winsys/svga/drm/vmw_screen.h
+++ b/src/gallium/winsys/svga/drm/vmw_screen.h
@@ -108,6 +108,7 @@ struct vmw_winsys_screen
    mtx_t cs_mutex;
 
    boolean force_coherent;
+   boolean cache_maps;
 };
 
 

diff --git a/src/gallium/winsys/svga/drm/vmw_screen_ioctl.c b/src/gallium/winsys/svga/drm/vmw_screen_ioctl.c
index 9696f884e4fd37c4909fa87dd1e702dda34f533a..bb3a1adedc1fa66f449410066ad838d06b9b5fb0 100644 (file)
--- a/src/gallium/winsys/svga/drm/vmw_screen_ioctl.c
+++ b/src/gallium/winsys/svga/drm/vmw_screen_ioctl.c
@@ -64,7 +64,6 @@ struct vmw_region
    uint32_t handle;
    uint64_t map_handle;
    void *data;
-   uint32_t map_count;
    int drm_fd;
    uint32_t size;
 };
@@ -637,7 +636,6 @@ vmw_ioctl_region_create(struct vmw_winsys_screen *vws, uint32_t size)
    region->data = NULL;
    region->handle = rep->handle;
    region->map_handle = rep->map_handle;
-   region->map_count = 0;
    region->size = size;
    region->drm_fd = vws->ioctl.drm_fd;
 
@@ -659,10 +657,7 @@ vmw_ioctl_region_destroy(struct vmw_region *region)
    vmw_printf("%s: gmrId = %u, offset = %u\n", __FUNCTION__,
               region->ptr.gmrId, region->ptr.offset);
 
-   if (region->data) {
-      os_munmap(region->data, region->size);
-      region->data = NULL;
-   }
+   assert(region->data == NULL);
 
    memset(&arg, 0, sizeof(arg));
    arg.handle = region->handle;
@@ -701,8 +696,6 @@ vmw_ioctl_region_map(struct vmw_region *region)
       region->data = map;
    }
 
-   ++region->map_count;
-
    return region->data;
 }
 
@@ -711,7 +704,9 @@ vmw_ioctl_region_unmap(struct vmw_region *region)
 {
    vmw_printf("%s: gmrId = %u, offset = %u\n", __FUNCTION__,
               region->ptr.gmrId, region->ptr.offset);
-   --region->map_count;
+
+   os_munmap(region->data, region->size);
+   region->data = NULL;
 }
 
 /**