xref: /dragonfly/contrib/zstd/lib/common/pool.h (revision c8860c9a)
1 /*
2  * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
3  * All rights reserved.
4  *
5  * This source code is licensed under both the BSD-style license (found in the
6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7  * in the COPYING file in the root directory of this source tree).
8  * You may select, at your option, one of the above-listed licenses.
9  */
10 
11 #ifndef POOL_H
12 #define POOL_H
13 
14 #if defined (__cplusplus)
15 extern "C" {
16 #endif
17 
18 
19 #include "zstd_deps.h"
20 #define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_customMem */
21 #include "../zstd.h"
22 
23 typedef struct POOL_ctx_s POOL_ctx;
24 
25 /*! POOL_create() :
26  *  Create a thread pool with at most `numThreads` threads.
27  * `numThreads` must be at least 1.
28  *  The maximum number of queued jobs before blocking is `queueSize`.
29  * @return : POOL_ctx pointer on success, else NULL.
30 */
31 POOL_ctx* POOL_create(size_t numThreads, size_t queueSize);
32 
33 POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize,
34                                ZSTD_customMem customMem);
35 
36 /*! POOL_free() :
37  *  Free a thread pool returned by POOL_create().
38  */
39 void POOL_free(POOL_ctx* ctx);
40 
41 /*! POOL_resize() :
42  *  Expands or shrinks pool's number of threads.
43  *  This is more efficient than releasing + creating a new context,
44  *  since it tries to preserve and re-use existing threads.
45  * `numThreads` must be at least 1.
46  * @return : 0 when resize was successful,
47  *           !0 (typically 1) if there is an error.
48  *    note : only numThreads can be resized, queueSize remains unchanged.
49  */
50 int POOL_resize(POOL_ctx* ctx, size_t numThreads);
51 
52 /*! POOL_sizeof() :
53  * @return threadpool memory usage
54  *  note : compatible with NULL (returns 0 in this case)
55  */
56 size_t POOL_sizeof(POOL_ctx* ctx);
57 
58 /*! POOL_function :
59  *  The function type that can be added to a thread pool.
60  */
61 typedef void (*POOL_function)(void*);
62 
63 /*! POOL_add() :
64  *  Add the job `function(opaque)` to the thread pool. `ctx` must be valid.
65  *  Possibly blocks until there is room in the queue.
66  *  Note : The function may be executed asynchronously,
67  *         therefore, `opaque` must live until function has been completed.
68  */
69 void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque);
70 
71 
72 /*! POOL_tryAdd() :
73  *  Add the job `function(opaque)` to thread pool _if_ a worker is available.
74  *  Returns immediately even if not (does not block).
75  * @return : 1 if successful, 0 if not.
76  */
77 int POOL_tryAdd(POOL_ctx* ctx, POOL_function function, void* opaque);
78 
79 
80 #if defined (__cplusplus)
81 }
82 #endif
83 
84 #endif
85