drm/ttm: Fix up io_mem_reserve / io_mem_free calling
This patch attempts to fix up shortcomings with the current calling
sequences.
1) There's a fastpath where no locking occurs and only io_mem_reserved is
called to obtain needed info for mapping. The fastpath is set per
memory type manager.
2) If the fastpath is disabled, io_mem_reserve and io_mem_free will be exactly
balanced and not called recursively for the same struct ttm_mem_reg.
3) Optionally the driver can choose to enable a per memory type manager LRU
eviction mechanism that, when io_mem_reserve returns -EAGAIN will attempt
to kill user-space mappings of memory in that manager to free up needed
resources
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index edacd48..50852aa 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -74,6 +74,8 @@
* @is_iomem: is this io memory ?
* @size: size in byte
* @offset: offset from the base address
+ * @io_reserved_vm: The VM system has a refcount in @io_reserved_count
+ * @io_reserved_count: Refcounting the numbers of callers to ttm_mem_io_reserve
*
* Structure indicating the bus placement of an object.
*/
@@ -83,7 +85,8 @@
unsigned long size;
unsigned long offset;
bool is_iomem;
- bool io_reserved;
+ bool io_reserved_vm;
+ uint64_t io_reserved_count;
};
@@ -235,6 +238,7 @@
struct list_head lru;
struct list_head ddestroy;
struct list_head swap;
+ struct list_head io_reserve_lru;
uint32_t val_seq;
bool seq_valid;