handletablesimple.cpp@ 18100

Last change on this file since 18100 was 10790, checked in by vboxsync, 16 years ago
IPRT: Fixed an overlooked race found by the threaded testcase.
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 10.1 KB

Line
1	/* $Id: handletablesimple.cpp 10790 2008-07-21 18:43:39Z vboxsync $ */
2	/** @file
3	* IPRT - Handle Tables.
4	*/
5
6	/*
7	* Copyright (C) 2008 Sun Microsystems, Inc.
8	*
9	* This file is part of VirtualBox Open Source Edition (OSE), as
10	* available from http://www.virtualbox.org. This file is free software;
11	* you can redistribute it and/or modify it under the terms of the GNU
12	* General Public License (GPL) as published by the Free Software
13	* Foundation, in version 2 as it comes in the "COPYING" file of the
14	* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	*
17	* The contents of this file may alternatively be used under the terms
18	* of the Common Development and Distribution License Version 1.0
19	* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	* VirtualBox OSE distribution, in which case the provisions of the
21	* CDDL are applicable instead of those of the GPL.
22	*
23	* You may elect to license modified versions of this file under the
24	* terms and conditions of either the GPL or the CDDL or both.
25	*
26	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
27	* Clara, CA 95054 USA or visit http://www.sun.com if you need
28	* additional information or have any questions.
29	*/
30
31	/*******************************************************************************
32	* Header Files *
33	*******************************************************************************/
34	#include <iprt/handletable.h>
35	#include <iprt/mem.h>
36	#include <iprt/spinlock.h>
37	#include <iprt/err.h>
38	#include <iprt/assert.h>
39	#include <iprt/param.h>
40	#include <iprt/string.h>
41	#include <iprt/asm.h>
42	#include "internal/magics.h"
43	#include "handletable.h"
44
45
46	RTDECL(int) RTHandleTableAlloc(RTHANDLETABLE hHandleTable, void pvObj, uint32_t ph)
47	{
48	/* validate the input */
49	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
50	AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
51	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, VERR_INVALID_HANDLE);
52	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), VERR_INVALID_FUNCTION);
53	AssertReturn(!RTHT_IS_FREE(pvObj), VERR_INVALID_PARAMETER);
54	AssertPtrReturn(ph, VERR_INVALID_POINTER);
55	*ph = pThis->uBase - 1;
56
57	/*
58	* Allocation loop.
59	*/
60	RTSPINLOCKTMP Tmp;
61	rtHandleTableLock(pThis, &Tmp);
62
63	int rc;
64	do
65	{
66	/*
67	* Try grab a free entry from the head of the free list.
68	*/
69	uint32_t i = pThis->iFreeHead;
70	if (i != NIL_RTHT_INDEX)
71	{
72	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, i);
73	Assert(pFree);
74	if (i == pThis->iFreeTail)
75	pThis->iFreeTail = pThis->iFreeHead = NIL_RTHT_INDEX;
76	else
77	pThis->iFreeHead = RTHT_GET_FREE_IDX(pFree);
78	pThis->cCurAllocated++;
79	Assert(pThis->cCurAllocated <= pThis->cCur);
80
81	/*
82	* Setup the entry and return.
83	*/
84	PRTHTENTRY pEntry = (PRTHTENTRY)pFree;
85	pEntry->pvObj = pvObj;
86	*ph = i + pThis->uBase;
87	rc = VINF_SUCCESS;
88	}
89	/*
90	* Must expand the handle table, unless it's full.
91	*/
92	else if (pThis->cCur >= pThis->cMax)
93	{
94	rc = VERR_NO_MORE_HANDLES;
95	Assert(pThis->cCur == pThis->cCurAllocated);
96	}
97	else
98	{
99	/*
100	* Do we have to expand the 1st level table too?
101	*/
102	uint32_t const iLevel1 = pThis->cCur / RTHT_LEVEL2_ENTRIES;
103	uint32_t cLevel1 = iLevel1 >= pThis->cLevel1
104	? pThis->cLevel1 + PAGE_SIZE / sizeof(void *)
105	: 0;
106	if (cLevel1 > pThis->cMax / RTHT_LEVEL2_ENTRIES)
107	cLevel1 = pThis->cMax / RTHT_LEVEL2_ENTRIES;
108	Assert(!cLevel1 \|\| pThis->cMax / RTHT_LEVEL2_ENTRIES >= RTHT_LEVEL1_DYN_ALLOC_THRESHOLD);
109
110	/* leave the lock (never do fancy stuff from behind a spinlock). */
111	rtHandleTableUnlock(pThis, &Tmp);
112
113	/*
114	* Do the allocation(s).
115	*/
116	rc = VERR_TRY_AGAIN;
117	void **papvLevel1 = NULL;
118	if (cLevel1)
119	{
120	papvLevel1 = (void *)RTMemAlloc(sizeof(void ) * cLevel1);
121	if (!papvLevel1)
122	return VERR_NO_MEMORY;
123	}
124
125	PRTHTENTRY paTable = (PRTHTENTRY)RTMemAlloc(sizeof(paTable) RTHT_LEVEL2_ENTRIES);
126	if (!paTable)
127	{
128	RTMemFree(papvLevel1);
129	return VERR_NO_MEMORY;
130	}
131
132	/* re-enter the lock. */
133	rtHandleTableLock(pThis, &Tmp);
134
135	/*
136	* Insert the new bits, but be a bit careful as someone might have
137	* raced us expanding the table.
138	*/
139	/* deal with the 1st level lookup expansion first */
140	if (cLevel1)
141	{
142	Assert(papvLevel1);
143	if (cLevel1 > pThis->cLevel1)
144	{
145	/* Replace the 1st level table. */
146	memcpy(papvLevel1, pThis->papvLevel1, sizeof(void ) pThis->cLevel1);
147	memset(&papvLevel1[pThis->cLevel1], 0, sizeof(void ) (cLevel1 - pThis->cLevel1));
148	pThis->cLevel1 = cLevel1;
149	void **papvTmp = pThis->papvLevel1;
150	pThis->papvLevel1 = papvLevel1;
151	papvLevel1 = papvTmp;
152	}
153
154	/* free the obsolete one (outside the lock of course) */
155	rtHandleTableUnlock(pThis, &Tmp);
156	RTMemFree(papvLevel1);
157	rtHandleTableLock(pThis, &Tmp);
158	}
159
160	/* insert the table we allocated. */
161	uint32_t iLevel1New = pThis->cCur / RTHT_LEVEL2_ENTRIES;
162	if ( iLevel1New < pThis->cLevel1
163	&& pThis->cCur < pThis->cMax)
164	{
165	pThis->papvLevel1[iLevel1New] = paTable;
166
167	/* link all entries into a free list. */
168	Assert(!(pThis->cCur % RTHT_LEVEL2_ENTRIES));
169	for (uint32_t i = 0; i < RTHT_LEVEL2_ENTRIES - 1; i++)
170	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[i], i + 1 + pThis->cCur);
171	RTHT_SET_FREE_IDX((PRTHTENTRYFREE)&paTable[RTHT_LEVEL2_ENTRIES - 1], NIL_RTHT_INDEX);
172
173	/* join the free list with the other. */
174	if (pThis->iFreeTail == NIL_RTHT_INDEX)
175	pThis->iFreeHead = pThis->cCur;
176	else
177	{
178	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
179	Assert(pPrev);
180	RTHT_SET_FREE_IDX(pPrev, pThis->cCur);
181	}
182	pThis->iFreeTail = pThis->cCur + RTHT_LEVEL2_ENTRIES - 1;
183
184	pThis->cCur += RTHT_LEVEL2_ENTRIES;
185	}
186	else
187	{
188	/* free the table (raced someone, and we lost). */
189	rtHandleTableUnlock(pThis, &Tmp);
190	RTMemFree(paTable);
191	rtHandleTableLock(pThis, &Tmp);
192	}
193
194	rc = VERR_TRY_AGAIN;
195	}
196	} while (rc == VERR_TRY_AGAIN);
197
198	rtHandleTableUnlock(pThis, &Tmp);
199
200	return rc;
201	}
202
203
204	RTDECL(void *) RTHandleTableLookup(RTHANDLETABLE hHandleTable, uint32_t h)
205	{
206	/* validate the input */
207	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
208	AssertPtrReturn(pThis, NULL);
209	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
210	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
211
212	void *pvObj = NULL;
213
214	/* acquire the lock */
215	RTSPINLOCKTMP Tmp;
216	rtHandleTableLock(pThis, &Tmp);
217
218	/*
219	* Perform the lookup and retaining.
220	*/
221	PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
222	if (pEntry)
223	{
224	pvObj = pEntry->pvObj;
225	if (!RTHT_IS_FREE(pvObj))
226	{
227	if (pThis->pfnRetain)
228	{
229	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
230	if (RT_FAILURE(rc))
231	pvObj = NULL;
232	}
233	}
234	else
235	pvObj = NULL;
236	}
237
238	/* release the lock */
239	rtHandleTableUnlock(pThis, &Tmp);
240	return pvObj;
241	}
242
243
244	RTDECL(void *) RTHandleTableFree(RTHANDLETABLE hHandleTable, uint32_t h)
245	{
246	/* validate the input */
247	PRTHANDLETABLEINT pThis = (PRTHANDLETABLEINT)hHandleTable;
248	AssertPtrReturn(pThis, NULL);
249	AssertReturn(pThis->u32Magic == RTHANDLETABLE_MAGIC, NULL);
250	AssertReturn(!(pThis->fFlags & RTHANDLETABLE_FLAGS_CONTEXT), NULL);
251
252	void *pvObj = NULL;
253
254	/* acquire the lock */
255	RTSPINLOCKTMP Tmp;
256	rtHandleTableLock(pThis, &Tmp);
257
258	/*
259	* Perform the lookup and retaining.
260	*/
261	PRTHTENTRY pEntry = rtHandleTableLookupSimple(pThis, h);
262	if (pEntry)
263	{
264	pvObj = pEntry->pvObj;
265	if (!RTHT_IS_FREE(pvObj))
266	{
267	if (pThis->pfnRetain)
268	{
269	int rc = pThis->pfnRetain(hHandleTable, pEntry->pvObj, NULL, pThis->pvRetainUser);
270	if (RT_FAILURE(rc))
271	pvObj = NULL;
272	}
273
274	/*
275	* Link it into the free list.
276	*/
277	if (pvObj)
278	{
279	PRTHTENTRYFREE pFree = (PRTHTENTRYFREE)pEntry;
280	RTHT_SET_FREE_IDX(pFree, NIL_RTHT_INDEX);
281
282	uint32_t const i = h - pThis->uBase;
283	if (pThis->iFreeTail == NIL_RTHT_INDEX)
284	pThis->iFreeHead = pThis->iFreeTail = i;
285	else
286	{
287	PRTHTENTRYFREE pPrev = (PRTHTENTRYFREE)rtHandleTableLookupSimpleIdx(pThis, pThis->iFreeTail);
288	Assert(pPrev);
289	RTHT_SET_FREE_IDX(pPrev, i);
290	pThis->iFreeTail = i;
291	}
292
293	Assert(pThis->cCurAllocated > 0);
294	pThis->cCurAllocated--;
295	}
296	}
297	else
298	pvObj = NULL;
299	}
300
301	/* release the lock */
302	rtHandleTableUnlock(pThis, &Tmp);
303	return pvObj;
304	}
305

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source: vbox/trunk/src/VBox/Runtime/common/misc/handletablesimple.cpp@ 18100

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