From 5bfe6126f8bd7cd59bafd90658a12c19687a26fb Mon Sep 17 00:00:00 2001 From: Sergey Sharybin Date: Fri, 13 Apr 2018 13:31:55 +0200 Subject: Added lock-free single linked list implementation Only supports lock-free insertion for now, can not delete element or traverse the list at the same time. --- source/blender/blenlib/BLI_linklist_lockfree.h | 88 +++++++++++++++++++++ source/blender/blenlib/CMakeLists.txt | 3 +- .../blender/blenlib/intern/BLI_linklist_lockfree.c | 91 ++++++++++++++++++++++ 3 files changed, 181 insertions(+), 1 deletion(-) create mode 100644 source/blender/blenlib/BLI_linklist_lockfree.h create mode 100644 source/blender/blenlib/intern/BLI_linklist_lockfree.c (limited to 'source') diff --git a/source/blender/blenlib/BLI_linklist_lockfree.h b/source/blender/blenlib/BLI_linklist_lockfree.h new file mode 100644 index 00000000000..7e7400361e3 --- /dev/null +++ b/source/blender/blenlib/BLI_linklist_lockfree.h @@ -0,0 +1,88 @@ +/* + * ***** BEGIN GPL LICENSE BLOCK ***** + * + * 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; either version 2 + * of the License, or (at your option) any later version. + * + * 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, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) 2018 Blender Foundation. + * All rights reserved. + * + * Contributor(s): Sergey Sharybin. + * + * ***** END GPL LICENSE BLOCK ***** + */ + +#ifndef __BLI_LINKLIST_LOCKFREE_H__ +#define __BLI_LINKLIST_LOCKFREE_H__ + +/** \file BLI_linklist_lockfree.h + * \ingroup bli + */ + +#ifdef __cplusplus +extern "C" { +#endif + +typedef struct LockfreeLinkNode { + struct LockfreeLinkNode *next; + /* NOTE: "Subclass" this structure to add custom-defined data. */ +} LockfreeLinkNode; + +typedef struct LockfreeLinkList { + /* We keep a dummy node at the beginning of the list all the time. + * This allows us to make sure head and tail pointers are always + * valid, and saves from annoying exception cases in insert(). + */ + LockfreeLinkNode dummy_node; + /* NOTE: This fields might point to a dummy node. */ + LockfreeLinkNode *head, *tail; +} LockfreeLinkList; + +typedef void (*LockfreeeLinkNodeFreeFP)(void *link); + +/* ************************************************************************** */ +/* NOTE: These functions are NOT safe for use from threads. */ +/* NOTE: !!! I REPEAT: DO NOT USE THEM WITHOUT EXTERNAL LOCK !!! */ + +/* Make list ready for lock-free access. */ +void BLI_linklist_lockfree_init(LockfreeLinkList *list); + +/* Completely free the whole list, it is NOT re-usable after this. */ +void BLI_linklist_lockfree_free(LockfreeLinkList *list, + LockfreeeLinkNodeFreeFP free_func); + +/* Remove all the elements from the list, keep it usable for further + * inserts. + */ +void BLI_linklist_lockfree_clear(LockfreeLinkList *list, + LockfreeeLinkNodeFreeFP free_func); + + +/* Begin iteration of lock-free linked list, starting with a + * first user=defined node. Will ignore the dummy node. + */ +LockfreeLinkNode *BLI_linklist_lockfree_begin(LockfreeLinkList *list); + + +/* ************************************************************************** */ +/* NOTE: These functions are safe for use from threads. */ + +void BLI_linklist_lockfree_insert(LockfreeLinkList *list, + LockfreeLinkNode *node); + +#ifdef __cplusplus +} +#endif + +#endif /* __BLI_LINKLIST_H__ */ diff --git a/source/blender/blenlib/CMakeLists.txt b/source/blender/blenlib/CMakeLists.txt index 33a8379def5..f8fc2bfdcff 100644 --- a/source/blender/blenlib/CMakeLists.txt +++ b/source/blender/blenlib/CMakeLists.txt @@ -50,6 +50,7 @@ set(SRC intern/BLI_kdopbvh.c intern/BLI_kdtree.c intern/BLI_linklist.c + intern/BLI_linklist_lockfree.c intern/BLI_memarena.c intern/BLI_mempool.c intern/DLRB_tree.c @@ -163,7 +164,7 @@ set(SRC BLI_kdtree.h BLI_lasso_2d.h BLI_link_utils.h - BLI_linklist.h + BLI_linklist_lockfree.h BLI_linklist_stack.h BLI_listbase.h BLI_math.h diff --git a/source/blender/blenlib/intern/BLI_linklist_lockfree.c b/source/blender/blenlib/intern/BLI_linklist_lockfree.c new file mode 100644 index 00000000000..c004ddb6b66 --- /dev/null +++ b/source/blender/blenlib/intern/BLI_linklist_lockfree.c @@ -0,0 +1,91 @@ +/* + * ***** BEGIN GPL LICENSE BLOCK ***** + * + * 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; either version 2 + * of the License, or (at your option) any later version. + * + * 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, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * The Original Code is Copyright (C) 2018 Blender Foundation. + * All rights reserved. + * + * Contributor(s): Sergey Sharybin. + * + * ***** END GPL LICENSE BLOCK ***** + */ + +/** \file blender/blenlib/intern/BLI_linklist_lockfree.c + * \ingroup bli + */ + +#include "MEM_guardedalloc.h" + +#include "BLI_linklist_lockfree.h" +#include "BLI_strict_flags.h" + +#include "atomic_ops.h" + +void BLI_linklist_lockfree_init(LockfreeLinkList *list) +{ + list->dummy_node.next = NULL; + list->head = list->tail = &list->dummy_node; +} + +void BLI_linklist_lockfree_free(LockfreeLinkList *list, + LockfreeeLinkNodeFreeFP free_func) +{ + if (free_func != NULL) { + /* NOTE: We start from a first user-added node. */ + LockfreeLinkNode *node = list->head->next; + while (node != NULL) { + LockfreeLinkNode *node_next = node->next; + free_func(node); + node = node_next; + } + } +} + +void BLI_linklist_lockfree_clear(LockfreeLinkList *list, + LockfreeeLinkNodeFreeFP free_func) +{ + BLI_linklist_lockfree_free(list, free_func); + BLI_linklist_lockfree_init(list); +} + +void BLI_linklist_lockfree_insert(LockfreeLinkList *list, + LockfreeLinkNode *node) +{ + /* Based on: + * + * John D. Valois + * Implementing Lock-Free Queues + * + * http://people.csail.mit.edu/bushl2/rpi/portfolio/lockfree-grape/documents/lock-free-linked-lists.pdf + */ + bool keep_working; + LockfreeLinkNode *tail_node; + node->next = NULL; + do { + tail_node = list->tail; + keep_working = + (atomic_cas_ptr((void**)&tail_node->next, NULL, node) != NULL); + if (keep_working) { + atomic_cas_ptr((void**)&list->tail, tail_node, tail_node->next); + } + } while (keep_working); + atomic_cas_ptr((void**)&list->tail, tail_node, node); +} + +LockfreeLinkNode *BLI_linklist_lockfree_begin(LockfreeLinkList *list) +{ + return list->head->next; +} -- cgit v1.2.3