![Eric Anholt](/assets/img/avatar_default.png)
GEM allows the creation of persistent buffer objects accessible by the graphics device through new ioctls for managing execution of commands on the device. The userland API is almost entirely driver-specific to ensure that any driver building on this model can easily map the interface to individual driver requirements. GEM is used by the 2d driver for managing its internal state allocations and will be used for pixmap storage to reduce memory consumption and enable zero-copy GLX_EXT_texture_from_pixmap, and in the 3d driver is used to enable GL_EXT_framebuffer_object and GL_ARB_pixel_buffer_object. Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Dave Airlie <airlied@redhat.com>
299 lines
7.2 KiB
C
299 lines
7.2 KiB
C
/**************************************************************************
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*
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* Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
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* All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
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* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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* USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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*
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**************************************************************************/
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/*
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* Generic simple memory manager implementation. Intended to be used as a base
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* class implementation for more advanced memory managers.
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*
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* Note that the algorithm used is quite simple and there might be substantial
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* performance gains if a smarter free list is implemented. Currently it is just an
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* unordered stack of free regions. This could easily be improved if an RB-tree
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* is used instead. At least if we expect heavy fragmentation.
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*
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* Aligned allocations can also see improvement.
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*
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* Authors:
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* Thomas Hellström <thomas-at-tungstengraphics-dot-com>
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*/
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#include "drmP.h"
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#include <linux/slab.h>
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unsigned long drm_mm_tail_space(struct drm_mm *mm)
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{
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struct list_head *tail_node;
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struct drm_mm_node *entry;
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tail_node = mm->ml_entry.prev;
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entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
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if (!entry->free)
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return 0;
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return entry->size;
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}
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int drm_mm_remove_space_from_tail(struct drm_mm *mm, unsigned long size)
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{
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struct list_head *tail_node;
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struct drm_mm_node *entry;
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tail_node = mm->ml_entry.prev;
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entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
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if (!entry->free)
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return -ENOMEM;
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if (entry->size <= size)
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return -ENOMEM;
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entry->size -= size;
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return 0;
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}
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static int drm_mm_create_tail_node(struct drm_mm *mm,
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unsigned long start,
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unsigned long size)
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{
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struct drm_mm_node *child;
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child = (struct drm_mm_node *)
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drm_alloc(sizeof(*child), DRM_MEM_MM);
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if (!child)
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return -ENOMEM;
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child->free = 1;
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child->size = size;
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child->start = start;
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child->mm = mm;
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list_add_tail(&child->ml_entry, &mm->ml_entry);
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list_add_tail(&child->fl_entry, &mm->fl_entry);
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return 0;
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}
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int drm_mm_add_space_to_tail(struct drm_mm *mm, unsigned long size)
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{
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struct list_head *tail_node;
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struct drm_mm_node *entry;
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tail_node = mm->ml_entry.prev;
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entry = list_entry(tail_node, struct drm_mm_node, ml_entry);
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if (!entry->free) {
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return drm_mm_create_tail_node(mm, entry->start + entry->size, size);
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}
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entry->size += size;
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return 0;
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}
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static struct drm_mm_node *drm_mm_split_at_start(struct drm_mm_node *parent,
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unsigned long size)
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{
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struct drm_mm_node *child;
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child = (struct drm_mm_node *)
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drm_alloc(sizeof(*child), DRM_MEM_MM);
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if (!child)
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return NULL;
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INIT_LIST_HEAD(&child->fl_entry);
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child->free = 0;
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child->size = size;
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child->start = parent->start;
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child->mm = parent->mm;
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list_add_tail(&child->ml_entry, &parent->ml_entry);
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INIT_LIST_HEAD(&child->fl_entry);
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parent->size -= size;
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parent->start += size;
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return child;
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}
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struct drm_mm_node *drm_mm_get_block(struct drm_mm_node * parent,
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unsigned long size, unsigned alignment)
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{
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struct drm_mm_node *align_splitoff = NULL;
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struct drm_mm_node *child;
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unsigned tmp = 0;
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if (alignment)
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tmp = parent->start % alignment;
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if (tmp) {
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align_splitoff = drm_mm_split_at_start(parent, alignment - tmp);
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if (!align_splitoff)
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return NULL;
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}
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if (parent->size == size) {
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list_del_init(&parent->fl_entry);
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parent->free = 0;
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return parent;
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} else {
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child = drm_mm_split_at_start(parent, size);
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}
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if (align_splitoff)
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drm_mm_put_block(align_splitoff);
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return child;
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}
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EXPORT_SYMBOL(drm_mm_get_block);
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/*
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* Put a block. Merge with the previous and / or next block if they are free.
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* Otherwise add to the free stack.
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*/
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void drm_mm_put_block(struct drm_mm_node * cur)
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{
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struct drm_mm *mm = cur->mm;
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struct list_head *cur_head = &cur->ml_entry;
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struct list_head *root_head = &mm->ml_entry;
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struct drm_mm_node *prev_node = NULL;
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struct drm_mm_node *next_node;
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int merged = 0;
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if (cur_head->prev != root_head) {
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prev_node = list_entry(cur_head->prev, struct drm_mm_node, ml_entry);
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if (prev_node->free) {
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prev_node->size += cur->size;
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merged = 1;
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}
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}
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if (cur_head->next != root_head) {
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next_node = list_entry(cur_head->next, struct drm_mm_node, ml_entry);
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if (next_node->free) {
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if (merged) {
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prev_node->size += next_node->size;
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list_del(&next_node->ml_entry);
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list_del(&next_node->fl_entry);
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drm_free(next_node, sizeof(*next_node),
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DRM_MEM_MM);
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} else {
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next_node->size += cur->size;
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next_node->start = cur->start;
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merged = 1;
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}
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}
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}
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if (!merged) {
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cur->free = 1;
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list_add(&cur->fl_entry, &mm->fl_entry);
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} else {
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list_del(&cur->ml_entry);
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drm_free(cur, sizeof(*cur), DRM_MEM_MM);
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}
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}
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EXPORT_SYMBOL(drm_mm_put_block);
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struct drm_mm_node *drm_mm_search_free(const struct drm_mm * mm,
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unsigned long size,
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unsigned alignment, int best_match)
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{
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struct list_head *list;
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const struct list_head *free_stack = &mm->fl_entry;
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struct drm_mm_node *entry;
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struct drm_mm_node *best;
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unsigned long best_size;
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unsigned wasted;
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best = NULL;
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best_size = ~0UL;
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list_for_each(list, free_stack) {
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entry = list_entry(list, struct drm_mm_node, fl_entry);
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wasted = 0;
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if (entry->size < size)
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continue;
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if (alignment) {
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register unsigned tmp = entry->start % alignment;
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if (tmp)
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wasted += alignment - tmp;
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}
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if (entry->size >= size + wasted) {
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if (!best_match)
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return entry;
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if (size < best_size) {
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best = entry;
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best_size = entry->size;
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}
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}
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}
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return best;
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}
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int drm_mm_clean(struct drm_mm * mm)
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{
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struct list_head *head = &mm->ml_entry;
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return (head->next->next == head);
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}
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EXPORT_SYMBOL(drm_mm_search_free);
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int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
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{
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INIT_LIST_HEAD(&mm->ml_entry);
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INIT_LIST_HEAD(&mm->fl_entry);
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return drm_mm_create_tail_node(mm, start, size);
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}
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EXPORT_SYMBOL(drm_mm_init);
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void drm_mm_takedown(struct drm_mm * mm)
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{
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struct list_head *bnode = mm->fl_entry.next;
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struct drm_mm_node *entry;
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entry = list_entry(bnode, struct drm_mm_node, fl_entry);
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if (entry->ml_entry.next != &mm->ml_entry ||
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entry->fl_entry.next != &mm->fl_entry) {
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DRM_ERROR("Memory manager not clean. Delaying takedown\n");
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return;
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}
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list_del(&entry->fl_entry);
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list_del(&entry->ml_entry);
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drm_free(entry, sizeof(*entry), DRM_MEM_MM);
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}
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