1 /* Copyright (c) 2009-2018. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
6 #include "simgrid/modelchecker.h"
7 #include "src/internal_config.h"
8 #include "src/kernel/context/context_private.hpp"
9 #include "src/simix/ActorImpl.hpp"
10 #include "src/simix/smx_private.hpp"
11 #include "xbt/parmap.hpp"
13 #include "src/kernel/context/ContextSwapped.hpp"
14 #include "src/kernel/context/ContextUnix.hpp" // FIXME: temporary reverse import
24 #define _aligned_malloc __mingw_aligned_malloc
25 #define _aligned_free __mingw_aligned_free
29 #include <valgrind/valgrind.h>
32 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
38 /* Sequential execution */
39 unsigned long SwappedContext::process_index_;
41 /* Parallel execution */
42 simgrid::xbt::Parmap<smx_actor_t>* SwappedContext::parmap_;
43 std::atomic<uintptr_t> SwappedContext::threads_working_; /* number of threads that have started their work */
44 thread_local uintptr_t SwappedContext::worker_id_; /* thread-specific storage for the thread id */
45 std::vector<SwappedContext*> SwappedContext::workers_context_; /* space to save the worker's context in each thread */
47 SwappedContextFactory::SwappedContextFactory(std::string name)
48 : ContextFactory(name), parallel_(SIMIX_context_is_parallel())
50 SwappedContext::set_maestro(nullptr);
51 SwappedContext::initialize(parallel_);
53 SwappedContextFactory::~SwappedContextFactory()
55 SwappedContext::finalize();
57 /** Maestro wants to run all ready actors */
58 void SwappedContextFactory::run_all()
60 /* This function is called by maestro at the beginning of a scheduling round to get all working threads executing some
61 * stuff It is much easier to understand what happens if you see the working threads as bodies that swap their soul
62 * for the ones of the simulated processes that must run.
65 SwappedContext::threads_working_ = 0;
67 // We lazily create the parmap so that all options are actually processed when doing so.
68 if (SwappedContext::parmap_ == nullptr)
69 SwappedContext::parmap_ =
70 new simgrid::xbt::Parmap<smx_actor_t>(SIMIX_context_get_nthreads(), SIMIX_context_get_parallel_mode());
72 // Usually, Parmap::apply() executes the provided function on all elements of the array.
73 // Here, the executed function does not return the control to the parmap before all the array is processed:
74 // - suspend() should switch back to the worker_context (either maestro or one of its minions) to return
75 // the control to the parmap. Instead, it uses parmap_->next() to steal another work, and does it directly.
76 // It only yields back to worker_context when the work array is exhausted.
77 // - So, resume() is only launched from the parmap for the first job of each minion.
78 SwappedContext::parmap_->apply(
79 [](smx_actor_t process) {
80 SwappedContext* context = static_cast<SwappedContext*>(process->context_);
83 simix_global->process_to_run);
84 } else { // sequential execution
85 if (simix_global->process_to_run.empty())
87 smx_actor_t first_process = simix_global->process_to_run.front();
88 SwappedContext::process_index_ = 1;
89 /* execute the first process */
90 static_cast<SwappedContext*>(first_process->context_)->resume();
94 void SwappedContext::initialize(bool parallel)
96 parmap_ = nullptr; // will be created lazily with the right parameters if needed (ie, in parallel)
98 workers_context_.clear();
99 workers_context_.resize(SIMIX_context_get_nthreads(), nullptr);
103 void SwappedContext::finalize()
107 workers_context_.clear();
110 SwappedContext* SwappedContext::maestro_context_ = nullptr;
112 SwappedContext::SwappedContext(std::function<void()> code, void_pfn_smxprocess_t cleanup_func, smx_actor_t process,
113 SwappedContextFactory* factory)
114 : Context(std::move(code), cleanup_func, process), factory_(factory)
117 if (smx_context_guard_size > 0 && not MC_is_active()) {
119 #if !defined(PTH_STACKGROWTH) || (PTH_STACKGROWTH != -1)
121 "Stack overflow protection is known to be broken on your system: you stacks grow upwards (or detection is "
123 "Please disable stack guards with --cfg=contexts:guard-size:0");
124 /* Current code for stack overflow protection assumes that stacks are growing downward (PTH_STACKGROWTH == -1).
125 * Protected pages need to be put after the stack when PTH_STACKGROWTH == 1. */
128 size_t size = smx_context_stack_size + smx_context_guard_size;
130 /* Cannot use posix_memalign when SIMGRID_HAVE_MC. Align stack by hand, and save the
131 * pointer returned by xbt_malloc0. */
132 char* alloc = (char*)xbt_malloc0(size + xbt_pagesize);
133 stack_ = alloc - ((uintptr_t)alloc & (xbt_pagesize - 1)) + xbt_pagesize;
134 *((void**)stack_ - 1) = alloc;
135 #elif !defined(_WIN32)
136 if (posix_memalign(&this->stack_, xbt_pagesize, size) != 0)
137 xbt_die("Failed to allocate stack.");
139 this->stack_ = _aligned_malloc(size, xbt_pagesize);
143 if (mprotect(this->stack_, smx_context_guard_size, PROT_NONE) == -1) {
145 "Failed to protect stack: %s.\n"
146 "If you are running a lot of actors, you may be exceeding the amount of mappings allowed per process.\n"
147 "On Linux systems, change this value with sudo sysctl -w vm.max_map_count=newvalue (default value: 65536)\n"
148 "Please see http://simgrid.gforge.inria.fr/simgrid/latest/doc/html/options.html#options_virt for more "
151 /* This is fatal. We are going to fail at some point when we try reusing this. */
154 this->stack_ = (char*)this->stack_ + smx_context_guard_size;
156 this->stack_ = xbt_malloc0(smx_context_stack_size);
160 unsigned int valgrind_stack_id =
161 VALGRIND_STACK_REGISTER(this->stack_, (char*)this->stack_ + smx_context_stack_size);
162 memcpy((char*)this->stack_ + smx_context_usable_stack_size, &valgrind_stack_id, sizeof valgrind_stack_id);
167 SwappedContext::~SwappedContext()
169 if (stack_ == nullptr) // maestro has no extra stack
173 unsigned int valgrind_stack_id;
174 memcpy(&valgrind_stack_id, (char*)stack_ + smx_context_usable_stack_size, sizeof valgrind_stack_id);
175 VALGRIND_STACK_DEREGISTER(valgrind_stack_id);
179 if (smx_context_guard_size > 0 && not MC_is_active()) {
180 stack_ = (char*)stack_ - smx_context_guard_size;
181 if (mprotect(stack_, smx_context_guard_size, PROT_READ | PROT_WRITE) == -1) {
182 XBT_WARN("Failed to remove page protection: %s", strerror(errno));
183 /* try to pursue anyway */
186 /* Retrieve the saved pointer. See SIMIX_context_stack_new above. */
187 stack_ = *((void**)stack_ - 1);
190 #endif /* not windows */
195 /** Maestro wants to yield back to a given actor */
196 void SwappedContext::resume()
198 if (factory_->parallel_) {
200 } else { // sequential execution
201 // Maestro is always the calling thread of this function (ie, self() == maestro)
202 SwappedContext* old = static_cast<SwappedContext*>(self());
203 Context::set_current(this);
204 old->swap_into(this);
208 /** The actor wants to yield back to maestro */
209 void SwappedContext::suspend()
211 if (factory_->parallel_) {
213 } else { // sequential execution
214 /* determine the next context */
215 SwappedContext* next_context;
216 unsigned long int i = process_index_;
219 if (i < simix_global->process_to_run.size()) {
220 /* Actually swap into the next actor directly without transiting to maestro */
221 XBT_DEBUG("Run next process");
222 next_context = static_cast<SwappedContext*>(simix_global->process_to_run[i]->context_);
224 /* all processes were run, actually return to maestro */
225 XBT_DEBUG("No more process to run");
226 next_context = static_cast<SwappedContext*>(get_maestro());
228 Context::set_current(next_context);
229 this->swap_into(next_context);
233 } // namespace context
234 } // namespace kernel
235 } // namespace simgrid