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Commit c078aa2f authored by Thomas Hellstrom's avatar Thomas Hellstrom Committed by Dave Airlie
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drm/ttm: Add TTM execbuf utilities.



Utilities to reserve, unreserve and fence a list of TTM
buffer objects in a deadlock-safe manner.

Used by the vmwgfx driver.

Signed-off-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 4aff1013
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@@ -4,6 +4,6 @@
ccflags-y := -Iinclude/drm
ccflags-y := -Iinclude/drm
ttm-y := ttm_agp_backend.o ttm_memory.o ttm_tt.o ttm_bo.o \
ttm-y := ttm_agp_backend.o ttm_memory.o ttm_tt.o ttm_bo.o \
	ttm_bo_util.o ttm_bo_vm.o ttm_module.o ttm_global.o \
	ttm_bo_util.o ttm_bo_vm.o ttm_module.o ttm_global.o \
	ttm_object.o ttm_lock.o
	ttm_object.o ttm_lock.o ttm_execbuf_util.o


obj-$(CONFIG_DRM_TTM) += ttm.o
obj-$(CONFIG_DRM_TTM) += ttm.o
+117 −0
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/**************************************************************************
 *
 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/

#include "ttm/ttm_execbuf_util.h"
#include "ttm/ttm_bo_driver.h"
#include "ttm/ttm_placement.h"
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/module.h>

void ttm_eu_backoff_reservation(struct list_head *list)
{
	struct ttm_validate_buffer *entry;

	list_for_each_entry(entry, list, head) {
		struct ttm_buffer_object *bo = entry->bo;
		if (!entry->reserved)
			continue;

		entry->reserved = false;
		ttm_bo_unreserve(bo);
	}
}
EXPORT_SYMBOL(ttm_eu_backoff_reservation);

/*
 * Reserve buffers for validation.
 *
 * If a buffer in the list is marked for CPU access, we back off and
 * wait for that buffer to become free for GPU access.
 *
 * If a buffer is reserved for another validation, the validator with
 * the highest validation sequence backs off and waits for that buffer
 * to become unreserved. This prevents deadlocks when validating multiple
 * buffers in different orders.
 */

int ttm_eu_reserve_buffers(struct list_head *list, uint32_t val_seq)
{
	struct ttm_validate_buffer *entry;
	int ret;

retry:
	list_for_each_entry(entry, list, head) {
		struct ttm_buffer_object *bo = entry->bo;

		entry->reserved = false;
		ret = ttm_bo_reserve(bo, true, false, true, val_seq);
		if (ret != 0) {
			ttm_eu_backoff_reservation(list);
			if (ret == -EAGAIN) {
				ret = ttm_bo_wait_unreserved(bo, true);
				if (unlikely(ret != 0))
					return ret;
				goto retry;
			} else
				return ret;
		}

		entry->reserved = true;
		if (unlikely(atomic_read(&bo->cpu_writers) > 0)) {
			ttm_eu_backoff_reservation(list);
			ret = ttm_bo_wait_cpu(bo, false);
			if (ret)
				return ret;
			goto retry;
		}
	}
	return 0;
}
EXPORT_SYMBOL(ttm_eu_reserve_buffers);

void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj)
{
	struct ttm_validate_buffer *entry;

	list_for_each_entry(entry, list, head) {
		struct ttm_buffer_object *bo = entry->bo;
		struct ttm_bo_driver *driver = bo->bdev->driver;
		void *old_sync_obj;

		spin_lock(&bo->lock);
		old_sync_obj = bo->sync_obj;
		bo->sync_obj = driver->sync_obj_ref(sync_obj);
		bo->sync_obj_arg = entry->new_sync_obj_arg;
		spin_unlock(&bo->lock);
		ttm_bo_unreserve(bo);
		entry->reserved = false;
		if (old_sync_obj)
			driver->sync_obj_unref(&old_sync_obj);
	}
}
EXPORT_SYMBOL(ttm_eu_fence_buffer_objects);
+107 −0
Original line number Original line Diff line number Diff line
/**************************************************************************
 *
 * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/
/*
 * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
 */

#ifndef _TTM_EXECBUF_UTIL_H_
#define _TTM_EXECBUF_UTIL_H_

#include "ttm/ttm_bo_api.h"
#include <linux/list.h>

/**
 * struct ttm_validate_buffer
 *
 * @head:           list head for thread-private list.
 * @bo:             refcounted buffer object pointer.
 * @new_sync_obj_arg: New sync_obj_arg for @bo, to be used once
 * adding a new sync object.
 * @reservied:      Indicates whether @bo has been reserved for validation.
 */

struct ttm_validate_buffer {
	struct list_head head;
	struct ttm_buffer_object *bo;
	void *new_sync_obj_arg;
	bool reserved;
};

/**
 * function ttm_eu_backoff_reservation
 *
 * @list:     thread private list of ttm_validate_buffer structs.
 *
 * Undoes all buffer validation reservations for bos pointed to by
 * the list entries.
 */

extern void ttm_eu_backoff_reservation(struct list_head *list);

/**
 * function ttm_eu_reserve_buffers
 *
 * @list:    thread private list of ttm_validate_buffer structs.
 * @val_seq: A unique sequence number.
 *
 * Tries to reserve bos pointed to by the list entries for validation.
 * If the function returns 0, all buffers are marked as "unfenced",
 * taken off the lru lists and are not synced for write CPU usage.
 *
 * If the function detects a deadlock due to multiple threads trying to
 * reserve the same buffers in reverse order, all threads except one will
 * back off and retry. This function may sleep while waiting for
 * CPU write reservations to be cleared, and for other threads to
 * unreserve their buffers.
 *
 * This function may return -ERESTART or -EAGAIN if the calling process
 * receives a signal while waiting. In that case, no buffers on the list
 * will be reserved upon return.
 *
 * Buffers reserved by this function should be unreserved by
 * a call to either ttm_eu_backoff_reservation() or
 * ttm_eu_fence_buffer_objects() when command submission is complete or
 * has failed.
 */

extern int ttm_eu_reserve_buffers(struct list_head *list, uint32_t val_seq);

/**
 * function ttm_eu_fence_buffer_objects.
 *
 * @list:        thread private list of ttm_validate_buffer structs.
 * @sync_obj:    The new sync object for the buffers.
 *
 * This function should be called when command submission is complete, and
 * it will add a new sync object to bos pointed to by entries on @list.
 * It also unreserves all buffers, putting them on lru lists.
 *
 */

extern void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj);

#endif