From: Mathieu Desnoyers Date: Sat, 22 Jun 2013 17:19:36 +0000 (-0400) Subject: doc/examples: introduce urcu-flavors examples directory X-Git-Tag: v0.8.0~30 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=6df9f02d9de67572ab8bd34855eca233c16ced47;p=userspace-rcu.git doc/examples: introduce urcu-flavors examples directory Signed-off-by: Mathieu Desnoyers --- diff --git a/doc/examples/Makefile.am b/doc/examples/Makefile.am index 74e2666..5db9fd5 100644 --- a/doc/examples/Makefile.am +++ b/doc/examples/Makefile.am @@ -1,11 +1,11 @@ doc_examplesdir = ${docdir}/examples -doc_examples_rcu_flavor_qsbrdir = ${doc_examplesdir}/rcu-flavor-qsbr +doc_examples_urcu_flavorsdir = ${doc_examplesdir}/urcu-flavors -dist_doc_examples_rcu_flavor_qsbr_DATA = \ - rcu-flavor-qsbr/Makefile \ - rcu-flavor-qsbr/Makefile.rcu-flavor-qsbr \ - rcu-flavor-qsbr/rcu-flavor-qsbr.c +dist_doc_examples_urcu_flavors_DATA = \ + urcu-flavors/Makefile \ + urcu-flavors/Makefile.qsbr \ + urcu-flavors/qsbr.c dist_doc_examples_DATA = \ Makefile.examples.template diff --git a/doc/examples/rcu-flavor-qsbr/Makefile b/doc/examples/rcu-flavor-qsbr/Makefile deleted file mode 100644 index 8e50722..0000000 --- a/doc/examples/rcu-flavor-qsbr/Makefile +++ /dev/null @@ -1,19 +0,0 @@ -# Copyright (C) 2013 Mathieu Desnoyers -# -# THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED -# OR IMPLIED. ANY USE IS AT YOUR OWN RISK. -# -# Permission is hereby granted to use or copy this program for any -# purpose, provided the above notices are retained on all copies. -# Permission to modify the code and to distribute modified code is -# granted, provided the above notices are retained, and a notice that -# the code was modified is included with the above copyright notice. -# -# This makefile is purposefully kept simple to support GNU and BSD make. - -all: - $(MAKE) -f Makefile.rcu-flavor-qsbr - -.PHONY: clean -clean: - $(MAKE) -f Makefile.rcu-flavor-qsbr clean diff --git a/doc/examples/rcu-flavor-qsbr/Makefile.rcu-flavor-qsbr b/doc/examples/rcu-flavor-qsbr/Makefile.rcu-flavor-qsbr deleted file mode 100644 index fc85278..0000000 --- a/doc/examples/rcu-flavor-qsbr/Makefile.rcu-flavor-qsbr +++ /dev/null @@ -1,21 +0,0 @@ -# Copyright (C) 2013 Mathieu Desnoyers -# -# THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED -# OR IMPLIED. ANY USE IS AT YOUR OWN RISK. -# -# Permission is hereby granted to use or copy this program for any -# purpose, provided the above notices are retained on all copies. -# Permission to modify the code and to distribute modified code is -# granted, provided the above notices are retained, and a notice that -# the code was modified is included with the above copyright notice. -# -# This makefile is purposefully kept simple to support GNU and BSD make. - -EXAMPLE_NAME = rcu-flavor-qsbr - -SOURCES = $(EXAMPLE_NAME).c -OBJECTS = $(EXAMPLE_NAME).o -BINARY = $(EXAMPLE_NAME) -LIBS = -lurcu-qsbr - -include ../Makefile.examples.template diff --git a/doc/examples/rcu-flavor-qsbr/rcu-flavor-qsbr.c b/doc/examples/rcu-flavor-qsbr/rcu-flavor-qsbr.c deleted file mode 100644 index 2b722c0..0000000 --- a/doc/examples/rcu-flavor-qsbr/rcu-flavor-qsbr.c +++ /dev/null @@ -1,139 +0,0 @@ -/* - * Copyright (C) 2013 Mathieu Desnoyers - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * This library 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 - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - */ - -#include -#include -#include -#include - -#include /* QSBR RCU flavor */ -#include /* List example */ -#include /* For CAA_ARRAY_SIZE */ - -/* - * This is a mock-up example where updates and RCU traversals are - * performed by the same thread to keep things simple on purpose. - */ - -static CDS_LIST_HEAD(mylist); - -struct mynode { - uint64_t value; - struct cds_list_head node; /* linked-list chaining */ - struct rcu_head rcu_head; /* for call_rcu() */ -}; - -static -int add_node(uint64_t v) -{ - struct mynode *node; - - node = calloc(sizeof(*node), 1); - if (!node) - return -1; - node->value = v; - cds_list_add_rcu(&node->node, &mylist); - return 0; -} - -static -void rcu_free_node(struct rcu_head *rh) -{ - struct mynode *node = caa_container_of(rh, struct mynode, rcu_head); - - free(node); -} - -int main(int argc, char **argv) -{ - uint64_t values[] = { 42, 36, 24, }; - unsigned int i; - int ret; - struct mynode *node, *n; - - /* - * Each thread need using RCU read-side need to be explicitly - * registered. - */ - rcu_register_thread(); - - /* - * Adding nodes to the linked-list. Safe against concurrent - * RCU traversals, require mutual exclusion with list updates. - */ - for (i = 0; i < CAA_ARRAY_SIZE(values); i++) { - ret = add_node(values[i]); - if (ret) - goto end; - } - - /* - * For all RCU flavors except QSBR, we need to explicitly mark - * RCU read-side critical sections with rcu_read_lock() and - * rcu_read_unlock(). They can be nested. Those are no-ops for - * the QSBR flavor. - */ - rcu_read_lock(); - - /* - * RCU traversal of the linked list. - */ - cds_list_for_each_entry_rcu(node, &mylist, node) { - printf("Value: %" PRIu64 "\n", node->value); - } - rcu_read_unlock(); - - /* - * Removing nodes from linked list. Safe against concurrent RCU - * traversals, require mutual exclusion with list updates. - */ - cds_list_for_each_entry_safe(node, n, &mylist, node) { - cds_list_del_rcu(&node->node); - call_rcu(&node->rcu_head, rcu_free_node); - } - - /* - * For QSBR flavor, we need to explicitly announce quiescent - * states. Here is how it is done. This should be performed by - * every online registered RCU threads in the program - * periodically. - */ - rcu_quiescent_state(); - - /* - * For QSBR flavor, when a thread needs to be in a quiescent - * state for a long period of time, we use rcu_thread_offline() - * and rcu_thread_online(). - */ - rcu_thread_offline(); - - sleep(1); - - rcu_thread_online(); - - /* - * Waiting for previously called call_rcu handlers to complete - * before program exits, or in library destructors, is a good - * practice. - */ - rcu_barrier(); - -end: - rcu_unregister_thread(); - return ret; -} diff --git a/doc/examples/urcu-flavors/Makefile b/doc/examples/urcu-flavors/Makefile new file mode 100644 index 0000000..80278e8 --- /dev/null +++ b/doc/examples/urcu-flavors/Makefile @@ -0,0 +1,19 @@ +# Copyright (C) 2013 Mathieu Desnoyers +# +# THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED +# OR IMPLIED. ANY USE IS AT YOUR OWN RISK. +# +# Permission is hereby granted to use or copy this program for any +# purpose, provided the above notices are retained on all copies. +# Permission to modify the code and to distribute modified code is +# granted, provided the above notices are retained, and a notice that +# the code was modified is included with the above copyright notice. +# +# This makefile is purposefully kept simple to support GNU and BSD make. + +all: + $(MAKE) -f Makefile.qsbr + +.PHONY: clean +clean: + $(MAKE) -f Makefile.qsbr clean diff --git a/doc/examples/urcu-flavors/Makefile.qsbr b/doc/examples/urcu-flavors/Makefile.qsbr new file mode 100644 index 0000000..dc28ddd --- /dev/null +++ b/doc/examples/urcu-flavors/Makefile.qsbr @@ -0,0 +1,21 @@ +# Copyright (C) 2013 Mathieu Desnoyers +# +# THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED +# OR IMPLIED. ANY USE IS AT YOUR OWN RISK. +# +# Permission is hereby granted to use or copy this program for any +# purpose, provided the above notices are retained on all copies. +# Permission to modify the code and to distribute modified code is +# granted, provided the above notices are retained, and a notice that +# the code was modified is included with the above copyright notice. +# +# This makefile is purposefully kept simple to support GNU and BSD make. + +EXAMPLE_NAME = qsbr + +SOURCES = $(EXAMPLE_NAME).c +OBJECTS = $(EXAMPLE_NAME).o +BINARY = $(EXAMPLE_NAME) +LIBS = -lurcu-qsbr + +include ../Makefile.examples.template diff --git a/doc/examples/urcu-flavors/qsbr.c b/doc/examples/urcu-flavors/qsbr.c new file mode 100644 index 0000000..1c50b8a --- /dev/null +++ b/doc/examples/urcu-flavors/qsbr.c @@ -0,0 +1,141 @@ +/* + * Copyright (C) 2013 Mathieu Desnoyers + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include +#include +#include +#include + +#include /* QSBR RCU flavor */ +#include /* List example */ +#include /* For CAA_ARRAY_SIZE */ + +/* + * Example showing how to use the QSBR Userspace RCU flavor. + * + * This is a mock-up example where updates and RCU traversals are + * performed by the same thread to keep things simple on purpose. + */ + +static CDS_LIST_HEAD(mylist); + +struct mynode { + uint64_t value; + struct cds_list_head node; /* linked-list chaining */ + struct rcu_head rcu_head; /* for call_rcu() */ +}; + +static +int add_node(uint64_t v) +{ + struct mynode *node; + + node = calloc(sizeof(*node), 1); + if (!node) + return -1; + node->value = v; + cds_list_add_rcu(&node->node, &mylist); + return 0; +} + +static +void rcu_free_node(struct rcu_head *rh) +{ + struct mynode *node = caa_container_of(rh, struct mynode, rcu_head); + + free(node); +} + +int main(int argc, char **argv) +{ + uint64_t values[] = { 42, 36, 24, }; + unsigned int i; + int ret; + struct mynode *node, *n; + + /* + * Each thread need using RCU read-side need to be explicitly + * registered. + */ + rcu_register_thread(); + + /* + * Adding nodes to the linked-list. Safe against concurrent + * RCU traversals, require mutual exclusion with list updates. + */ + for (i = 0; i < CAA_ARRAY_SIZE(values); i++) { + ret = add_node(values[i]); + if (ret) + goto end; + } + + /* + * For all RCU flavors except QSBR, we need to explicitly mark + * RCU read-side critical sections with rcu_read_lock() and + * rcu_read_unlock(). They can be nested. Those are no-ops for + * the QSBR flavor. + */ + rcu_read_lock(); + + /* + * RCU traversal of the linked list. + */ + cds_list_for_each_entry_rcu(node, &mylist, node) { + printf("Value: %" PRIu64 "\n", node->value); + } + rcu_read_unlock(); + + /* + * Removing nodes from linked list. Safe against concurrent RCU + * traversals, require mutual exclusion with list updates. + */ + cds_list_for_each_entry_safe(node, n, &mylist, node) { + cds_list_del_rcu(&node->node); + call_rcu(&node->rcu_head, rcu_free_node); + } + + /* + * For QSBR flavor, we need to explicitly announce quiescent + * states. Here is how it is done. This should be performed by + * every online registered RCU threads in the program + * periodically. + */ + rcu_quiescent_state(); + + /* + * For QSBR flavor, when a thread needs to be in a quiescent + * state for a long period of time, we use rcu_thread_offline() + * and rcu_thread_online(). + */ + rcu_thread_offline(); + + sleep(1); + + rcu_thread_online(); + + /* + * Waiting for previously called call_rcu handlers to complete + * before program exits, or in library destructors, is a good + * practice. + */ + rcu_barrier(); + +end: + rcu_unregister_thread(); + return ret; +}