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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:17:27 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:17:27 +0000 |
commit | f215e02bf85f68d3a6106c2a1f4f7f063f819064 (patch) | |
tree | 6bb5b92c046312c4e95ac2620b10ddf482d3fa8b /include/iprt/queueatomic.h | |
parent | Initial commit. (diff) | |
download | virtualbox-f215e02bf85f68d3a6106c2a1f4f7f063f819064.tar.xz virtualbox-f215e02bf85f68d3a6106c2a1f4f7f063f819064.zip |
Adding upstream version 7.0.14-dfsg.upstream/7.0.14-dfsg
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | include/iprt/queueatomic.h | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/include/iprt/queueatomic.h b/include/iprt/queueatomic.h new file mode 100644 index 00000000..bb3c4a71 --- /dev/null +++ b/include/iprt/queueatomic.h @@ -0,0 +1,137 @@ +/** @file + * IPRT - Generic Work Queue with concurrent atomic access. + */ + +/* + * Copyright (C) 2013-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + +#ifndef IPRT_INCLUDED_queueatomic_h +#define IPRT_INCLUDED_queueatomic_h +#ifndef RT_WITHOUT_PRAGMA_ONCE +# pragma once +#endif + +#include <iprt/types.h> +#include <iprt/asm.h> + +/** @defgroup grp_rt_queueatomic RTQueueAtomic - Generic Work Queue + * @ingroup grp_rt + * + * Implementation of a lockless work queue for threaded environments. + * @{ + */ + +RT_C_DECLS_BEGIN + +/** + * A work item + */ +typedef struct RTQUEUEATOMICITEM +{ + /** Pointer to the next work item in the list. */ + struct RTQUEUEATOMICITEM * volatile pNext; +} RTQUEUEATOMICITEM; +/** Pointer to a work item. */ +typedef RTQUEUEATOMICITEM *PRTQUEUEATOMICITEM; +/** Pointer to a work item pointer. */ +typedef PRTQUEUEATOMICITEM *PPRTQUEUEATOMICITEM; + +/** + * Work queue. + */ +typedef struct RTQUEUEATOMIC +{ + /* Head of the work queue. */ + volatile PRTQUEUEATOMICITEM pHead; +} RTQUEUEATOMIC; +/** Pointer to a work queue. */ +typedef RTQUEUEATOMIC *PRTQUEUEATOMIC; + +/** + * Initialize a work queue. + * + * @param pWorkQueue Pointer to an unitialised work queue. + */ +DECLINLINE(void) RTQueueAtomicInit(PRTQUEUEATOMIC pWorkQueue) +{ + ASMAtomicWriteNullPtr(&pWorkQueue->pHead); +} + +/** + * Insert a new item into the work queue. + * + * @param pWorkQueue The work queue to insert into. + * @param pItem The item to insert. + */ +DECLINLINE(void) RTQueueAtomicInsert(PRTQUEUEATOMIC pWorkQueue, PRTQUEUEATOMICITEM pItem) +{ + PRTQUEUEATOMICITEM pNext = ASMAtomicUoReadPtrT(&pWorkQueue->pHead, PRTQUEUEATOMICITEM); + PRTQUEUEATOMICITEM pHeadOld; + pItem->pNext = pNext; + while (!ASMAtomicCmpXchgExPtr(&pWorkQueue->pHead, pItem, pNext, &pHeadOld)) + { + pNext = pHeadOld; + Assert(pNext != pItem); + pItem->pNext = pNext; + ASMNopPause(); + } +} + +/** + * Remove all items from the given work queue and return them in the inserted order. + * + * @returns Pointer to the first item. + * @param pWorkQueue The work queue. + */ +DECLINLINE(PRTQUEUEATOMICITEM) RTQueueAtomicRemoveAll(PRTQUEUEATOMIC pWorkQueue) +{ + PRTQUEUEATOMICITEM pHead = ASMAtomicXchgPtrT(&pWorkQueue->pHead, NULL, PRTQUEUEATOMICITEM); + + /* Reverse it. */ + PRTQUEUEATOMICITEM pCur = pHead; + pHead = NULL; + while (pCur) + { + PRTQUEUEATOMICITEM pInsert = pCur; + pCur = pCur->pNext; + pInsert->pNext = pHead; + pHead = pInsert; + } + + return pHead; +} + +RT_C_DECLS_END + +/** @} */ + +#endif /* !IPRT_INCLUDED_queueatomic_h */ + |