pb_slab.h revision b8e80941 
1/*
2 * Copyright 2016 Advanced Micro Devices, Inc.
3 * All Rights Reserved.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining
6 * a copy of this software and associated documentation files (the
7 * "Software"), to deal in the Software without restriction, including
8 * without limitation the rights to use, copy, modify, merge, publish,
9 * distribute, sub license, and/or sell copies of the Software, and to
10 * permit persons to whom the Software is furnished to do so, subject to
11 * the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the
14 * next paragraph) shall be included in all copies or substantial portions
15 * of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
19 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 * NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS, AUTHORS
21 * AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
23 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 */
27
28/**
29 * \file
30 *
31 * Helper library for carving out smaller allocations (called "(slab) entries")
32 * from larger buffers (called "slabs").
33 *
34 * The library supports maintaining separate heaps (e.g. VRAM vs. GTT). The
35 * meaning of each heap is treated as opaque by this library.
36 *
37 * The library allows delaying the re-use of an entry, i.e. an entry may be
38 * freed by calling \ref pb_slab_free even while the corresponding buffer
39 * region is still in use by the GPU. A callback function is called to
40 * determine when it is safe to allocate the entry again; the user of this
41 * library is expected to maintain the required fences or similar.
42 */
43
44#ifndef PB_SLAB_H
45#define PB_SLAB_H
46
47#include "pb_buffer.h"
48#include "util/list.h"
49#include "os/os_thread.h"
50
51struct pb_slab;
52struct pb_slabs;
53struct pb_slab_group;
54
55/* Descriptor of a slab entry.
56 *
57 * The user of this utility library is expected to embed this in a larger
58 * structure that describes a buffer object.
59 */
60struct pb_slab_entry
61{
62   struct list_head head;
63   struct pb_slab *slab; /* the slab that contains this buffer */
64   unsigned group_index; /* index into pb_slabs::groups */
65};
66
67/* Descriptor of a slab from which many entries are carved out.
68 *
69 * The user of this utility library is expected to embed this in a larger
70 * structure that describes a buffer object.
71 */
72struct pb_slab
73{
74   struct list_head head;
75
76   struct list_head free; /* list of free pb_slab_entry structures */
77   unsigned num_free; /* number of entries in free list */
78   unsigned num_entries; /* total number of entries */
79};
80
81/* Callback function that is called when a new slab needs to be allocated
82 * for fulfilling allocation requests of the given size from the given heap.
83 *
84 * The callback must allocate a pb_slab structure and the desired number
85 * of entries. All entries that belong to the slab must be added to the free
86 * list. Entries' pb_slab_entry structures must be initialized with the given
87 * group_index.
88 *
89 * The callback may call pb_slab functions.
90 */
91typedef struct pb_slab *(slab_alloc_fn)(void *priv,
92                                        unsigned heap,
93                                        unsigned entry_size,
94                                        unsigned group_index);
95
96/* Callback function that is called when all entries of a slab have been freed.
97 *
98 * The callback must free the slab and all its entries. It must not call any of
99 * the pb_slab functions, or a deadlock (recursive mutex lock) may occur.
100 */
101typedef void (slab_free_fn)(void *priv, struct pb_slab *);
102
103/* Callback function to determine whether a given entry can already be reused.
104 */
105typedef bool (slab_can_reclaim_fn)(void *priv, struct pb_slab_entry *);
106
107/* Manager of slab allocations. The user of this utility library should embed
108 * this in a structure somewhere and call pb_slab_init/deinit at init/shutdown
109 * time.
110 */
111struct pb_slabs
112{
113   mtx_t mutex;
114
115   unsigned min_order;
116   unsigned num_orders;
117   unsigned num_heaps;
118
119   /* One group per (heap, order) pair. */
120   struct pb_slab_group *groups;
121
122   /* List of entries waiting to be reclaimed, i.e. they have been passed to
123    * pb_slab_free, but may not be safe for re-use yet. The tail points at
124    * the most-recently freed entry.
125    */
126   struct list_head reclaim;
127
128   void *priv;
129   slab_can_reclaim_fn *can_reclaim;
130   slab_alloc_fn *slab_alloc;
131   slab_free_fn *slab_free;
132};
133
134struct pb_slab_entry *
135pb_slab_alloc(struct pb_slabs *slabs, unsigned size, unsigned heap);
136
137void
138pb_slab_free(struct pb_slabs* slabs, struct pb_slab_entry *entry);
139
140void
141pb_slabs_reclaim(struct pb_slabs *slabs);
142
143bool
144pb_slabs_init(struct pb_slabs *slabs,
145              unsigned min_order, unsigned max_order,
146              unsigned num_heaps,
147              void *priv,
148              slab_can_reclaim_fn *can_reclaim,
149              slab_alloc_fn *slab_alloc,
150              slab_free_fn *slab_free);
151
152void
153pb_slabs_deinit(struct pb_slabs *slabs);
154
155#endif
156