drm_suballoc.c | Explore in Territory

// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
 * Copyright 2011 Red Hat Inc.
 * Copyright 2023 Intel Corporation.
 * 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 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.
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 */
/* Algorithm:
 *
 * We store the last allocated bo in "hole", we always try to allocate
 * after the last allocated bo. Principle is that in a linear GPU ring
 * progression was is after last is the oldest bo we allocated and thus
 * the first one that should no longer be in use by the GPU.
 *
 * If it's not the case we skip over the bo after last to the closest
 * done bo if such one exist. If none exist and we are not asked to
 * block we report failure to allocate.
 *
 * If we are asked to block we wait on all the oldest fence of all
 * rings. We just wait for any of those fence to complete.
 */

#include <drm/drm_suballoc.h>
#include <drm/drm_print.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/dma-fence.h>

static void drm_suballoc_remove_locked(struct drm_suballoc *sa);
static void drm_suballoc_try_free(struct drm_suballoc_manager *sa_manager);

/**
 * drm_suballoc_manager_init() - Initialise the drm_suballoc_manager
 * @sa_manager: pointer to the sa_manager
 * @size: number of bytes we want to suballocate
 * @align: alignment for each suballocated chunk
 *
 * Prepares the suballocation manager for suballocations.
 */
void drm_suballoc_manager_init(struct drm_suballoc_manager *sa_manager,
			       size_t size, size_t align)
{ … }
EXPORT_SYMBOL(…);

/**
 * drm_suballoc_manager_fini() - Destroy the drm_suballoc_manager
 * @sa_manager: pointer to the sa_manager
 *
 * Cleans up the suballocation manager after use. All fences added
 * with drm_suballoc_free() must be signaled, or we cannot clean up
 * the entire manager.
 */
void drm_suballoc_manager_fini(struct drm_suballoc_manager *sa_manager)
{ … }
EXPORT_SYMBOL(…);

static void drm_suballoc_remove_locked(struct drm_suballoc *sa)
{ … }

static void drm_suballoc_try_free(struct drm_suballoc_manager *sa_manager)
{ … }

static size_t drm_suballoc_hole_soffset(struct drm_suballoc_manager *sa_manager)
{ … }

static size_t drm_suballoc_hole_eoffset(struct drm_suballoc_manager *sa_manager)
{ … }

static bool drm_suballoc_try_alloc(struct drm_suballoc_manager *sa_manager,
				   struct drm_suballoc *sa,
				   size_t size, size_t align)
{ … }

static bool __drm_suballoc_event(struct drm_suballoc_manager *sa_manager,
				 size_t size, size_t align)
{ … }

/**
 * drm_suballoc_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
 *
 * Return: true if either there is a fence we can wait for or
 * enough free memory to satisfy the allocation directly.
 * false otherwise.
 */
static bool drm_suballoc_event(struct drm_suballoc_manager *sa_manager,
			       size_t size, size_t align)
{ … }

static bool drm_suballoc_next_hole(struct drm_suballoc_manager *sa_manager,
				   struct dma_fence **fences,
				   unsigned int *tries)
{ … }

/**
 * drm_suballoc_new() - Make a suballocation.
 * @sa_manager: pointer to the sa_manager
 * @size: number of bytes we want to suballocate.
 * @gfp: gfp flags used for memory allocation. Typically GFP_KERNEL but
 *       the argument is provided for suballocations from reclaim context or
 *       where the caller wants to avoid pipelining rather than wait for
 *       reclaim.
 * @intr: Whether to perform waits interruptible. This should typically
 *        always be true, unless the caller needs to propagate a
 *        non-interruptible context from above layers.
 * @align: Alignment. Must not exceed the default manager alignment.
 *         If @align is zero, then the manager alignment is used.
 *
 * Try to make a suballocation of size @size, which will be rounded
 * up to the alignment specified in specified in drm_suballoc_manager_init().
 *
 * Return: a new suballocated bo, or an ERR_PTR.
 */
struct drm_suballoc *
drm_suballoc_new(struct drm_suballoc_manager *sa_manager, size_t size,
		 gfp_t gfp, bool intr, size_t align)
{ … }
EXPORT_SYMBOL(…);

/**
 * drm_suballoc_free - Free a suballocation
 * @suballoc: pointer to the suballocation
 * @fence: fence that signals when suballocation is idle
 *
 * Free the suballocation. The suballocation can be re-used after @fence signals.
 */
void drm_suballoc_free(struct drm_suballoc *suballoc,
		       struct dma_fence *fence)
{ … }
EXPORT_SYMBOL(…);

#ifdef CONFIG_DEBUG_FS
void drm_suballoc_dump_debug_info(struct drm_suballoc_manager *sa_manager,
				  struct drm_printer *p,
				  unsigned long long suballoc_base)
{ … }
EXPORT_SYMBOL(…);
#endif
MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;
linux/drivers/gpu/drm/drm_suballoc.c
