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Member "mesa-20.1.8/src/gallium/drivers/nouveau/nouveau_heap.h" (16 Sep 2020, 2769 Bytes) of package /linux/misc/mesa-20.1.8.tar.xz:


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    1 /*
    2  * Copyright 2007 Nouveau Project
    3  *
    4  * Permission is hereby granted, free of charge, to any person obtaining a
    5  * copy of this software and associated documentation files (the "Software"),
    6  * to deal in the Software without restriction, including without limitation
    7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
    8  * and/or sell copies of the Software, and to permit persons to whom the
    9  * Software is furnished to do so, subject to the following conditions:
   10  *
   11  * The above copyright notice and this permission notice shall be included in
   12  * all copies or substantial portions of the Software.
   13  *
   14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
   18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   20  * OTHER DEALINGS IN THE SOFTWARE.
   21  */
   22 
   23 #ifndef __NOUVEAU_HEAP_H__
   24 #define __NOUVEAU_HEAP_H__
   25 
   26 /* This datastructure represents a memory allocation heap. Fundamentally, this
   27  * is a doubly-linked list with a few properties, and a usage convention.
   28  *
   29  * On initial allocation, there is a single node with the full size that's
   30  * marked as not in-use. As allocations are made, blocks are taken off the end
   31  * of that first node, and inserted right after it. If the first node doesn't
   32  * have enough free space, we look for free space down in the rest of the
   33  * list. This can happen if an allocation is made and then freed.
   34  *
   35  * The first node will remain with in_use == 0 even if the whole heap is
   36  * exhausted. Another invariant is that there will never be two sequential
   37  * in_use == 0 nodes. If a node is freed and it has one (or both) adjacent
   38  * free nodes, they are merged into one, and the relevant heap entries are
   39  * freed.
   40  *
   41  * The pattern to free the whole heap is to start with the first node and then
   42  * just free the "next" node, until there is no next node. This should assure
   43  * that at the end the first (and only) node is not in use and contains the
   44  * full size of the heap.
   45  */
   46 struct nouveau_heap {
   47    struct nouveau_heap *prev;
   48    struct nouveau_heap *next;
   49 
   50    void *priv;
   51 
   52    unsigned start;
   53    unsigned size;
   54 
   55    int in_use;
   56 };
   57 
   58 int
   59 nouveau_heap_init(struct nouveau_heap **heap, unsigned start,
   60                   unsigned size);
   61 
   62 void
   63 nouveau_heap_destroy(struct nouveau_heap **heap);
   64 
   65 int
   66 nouveau_heap_alloc(struct nouveau_heap *heap, unsigned size, void *priv,
   67                    struct nouveau_heap **);
   68 
   69 void
   70 nouveau_heap_free(struct nouveau_heap **);
   71 
   72 #endif