-/* Copyright (c) 2009-2018. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2009-2023. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
/* \file UContext.cpp Context switching with ucontexts from System V */
-#include "context_private.hpp"
-
#include "mc/mc.h"
#include "simgrid/Exception.hpp"
-#include "src/mc/mc_ignore.hpp"
-#include "src/simix/ActorImpl.hpp"
-#include "src/simix/smx_private.hpp"
+#include "src/kernel/actor/ActorImpl.hpp"
+#include "src/mc/remote/AppSide.hpp"
#include "ContextUnix.hpp"
-XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
+XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(ker_context);
-/** Many integers are needed to store a pointer
- *
- * Support up to two ints. */
+/** Up to two integers may be needed to store a pointer on the system we target */
constexpr int CTX_ADDR_LEN = 2;
static_assert(sizeof(simgrid::kernel::context::UContext*) <= CTX_ADDR_LEN * sizeof(int),
- "Ucontexts are not supported on this arch yet");
+ "Ucontexts are not supported on this arch yet. Please increase CTX_ADDR_LEN.");
+
+// This function is called by makecontext(3): use extern "C" to have C language linkage for its type
+extern "C" {
+XBT_ATTRIB_NORETURN static void sysv_ctx_wrapper(int i1, int i2)
+{
+ // Rebuild the Context* pointer from the integers:
+ int ctx_addr[CTX_ADDR_LEN] = {i1, i2};
+ simgrid::kernel::context::UContext* context;
+ memcpy(&context, ctx_addr, sizeof context);
+ smx_ctx_wrapper(context);
+}
+}
-namespace simgrid {
-namespace kernel {
-namespace context {
+namespace simgrid::kernel::context {
// UContextFactory
-Context* UContextFactory::create_context(std::function<void()> code, void_pfn_smxprocess_t cleanup, smx_actor_t process)
+UContext* UContextFactory::create_context(std::function<void()>&& code, actor::ActorImpl* actor)
{
- if (parallel_)
- return new_context<ParallelUContext>(std::move(code), cleanup, process, this);
- else
- return new_context<UContext>(std::move(code), cleanup, process, this);
+ return new_context<UContext>(std::move(code), actor, this);
}
// UContext
-UContext::UContext(std::function<void()> code, void_pfn_smxprocess_t cleanup_func, smx_actor_t process,
- SwappedContextFactory* factory)
- : SwappedContext(std::move(code), cleanup_func, process, factory)
+UContext::UContext(std::function<void()>&& code, actor::ActorImpl* actor, SwappedContextFactory* factory)
+ : SwappedContext(std::move(code), actor, factory)
{
- /* if the user provided a function for the process then use it, otherwise it is the context for maestro */
+ XBT_VERB("Creating a context of stack %uMb", actor->get_stacksize() / 1024 / 1024);
+ /* if the user provided a function for the actor then use it. If not, nothing to do for maestro. */
if (has_code()) {
getcontext(&this->uc_);
this->uc_.uc_link = nullptr;
- this->uc_.uc_stack.ss_sp = sg_makecontext_stack_addr(this->stack_);
- this->uc_.uc_stack.ss_size = sg_makecontext_stack_size(smx_context_usable_stack_size);
-#if PTH_STACKGROWTH == -1
- ASAN_ONLY(this->asan_stack_ = static_cast<char*>(this->stack_) + smx_context_usable_stack_size);
-#else
- ASAN_ONLY(this->asan_stack_ = this->stack_);
-#endif
- UContext::make_ctx(&this->uc_, UContext::smx_ctx_sysv_wrapper, this);
- } else {
- if (process != nullptr && get_maestro() == nullptr)
- set_maestro(this);
- }
+ this->uc_.uc_stack.ss_sp = sg_makecontext_stack_addr(get_stack());
+ this->uc_.uc_stack.ss_size = sg_makecontext_stack_size(actor->get_stacksize());
+ // Makecontext expects integer arguments; we want to pass a pointer.
+ // This context address is decomposed into a series of integers, which are passed as arguments to makecontext.
+
+ int ctx_addr[CTX_ADDR_LEN]{};
+ UContext* arg = this;
+ memcpy(ctx_addr, &arg, sizeof arg);
+ makecontext(&this->uc_, (void (*)())sysv_ctx_wrapper, 2, ctx_addr[0], ctx_addr[1]);
#if SIMGRID_HAVE_MC
- if (MC_is_active() && has_code()) {
- MC_register_stack_area(this->stack_, process, &(this->uc_), smx_context_usable_stack_size);
- }
+ if (MC_is_active())
+ simgrid::mc::AppSide::get()->declare_stack(get_stack(), stack_size, &uc_);
#endif
-}
-
-UContext::~UContext() = default;
-
-// The name of this function is currently hardcoded in the code (as string).
-// Do not change it without fixing those references as well.
-void UContext::smx_ctx_sysv_wrapper(int i1, int i2)
-{
- // Rebuild the Context* pointer from the integers:
- int ctx_addr[CTX_ADDR_LEN] = {i1, i2};
- simgrid::kernel::context::UContext* context;
- memcpy(&context, ctx_addr, sizeof context);
-
- ASAN_FINISH_SWITCH(nullptr, &context->asan_ctx_->asan_stack_, &context->asan_ctx_->asan_stack_size_);
- try {
- (*context)();
- } catch (simgrid::kernel::context::Context::StopRequest const&) {
- XBT_DEBUG("Caught a StopRequest");
- } catch (simgrid::Exception const& e) {
- XBT_INFO("Actor killed by an uncatched exception %s", simgrid::xbt::demangle(typeid(e).name()).get());
- throw;
}
- context->Context::stop();
- ASAN_ONLY(context->asan_stop_ = true);
- context->suspend();
-}
-
-/** A better makecontext
- *
- * Makecontext expects integer arguments, we the context variable is decomposed into a serie of integers and each
- * integer is passed as argument to makecontext.
- */
-void UContext::make_ctx(ucontext_t* ucp, void (*func)(int, int), UContext* arg)
-{
- int ctx_addr[CTX_ADDR_LEN]{};
- memcpy(ctx_addr, &arg, sizeof arg);
- makecontext(ucp, (void (*)())func, 2, ctx_addr[0], ctx_addr[1]);
}
-void UContext::swap_into(SwappedContext* to_)
+void UContext::swap_into_for_real(SwappedContext* to_)
{
- UContext* to = static_cast<UContext*>(to_);
- ASAN_ONLY(void* fake_stack = nullptr);
- ASAN_ONLY(to->asan_ctx_ = from);
- ASAN_START_SWITCH(from->asan_stop_ ? nullptr : &fake_stack, to->asan_stack_, to->asan_stack_size_);
+ const UContext* to = static_cast<UContext*>(to_);
swapcontext(&this->uc_, &to->uc_);
- ASAN_FINISH_SWITCH(fake_stack, &from->asan_ctx_->asan_stack_, &from->asan_ctx_->asan_stack_size_);
}
-// ParallelUContext
-
-/** Run one particular simulated process on the current thread.
- *
- * Only applied to the N first elements of the parmap array, where N is the amount of worker threads in the parmap.
- * See ParallelUContext::run_all for details.
- */
-void ParallelUContext::resume()
-{
- // Save the thread number (my body) in an os-thread-specific area
- worker_id_ = threads_working_.fetch_add(1, std::memory_order_relaxed);
- // Save my current soul (either maestro, or one of the minions) in a permanent area
- SwappedContext* worker_context = static_cast<SwappedContext*>(self());
- workers_context_[worker_id_] = worker_context;
- // Switch my soul and the actor's one
- Context::set_current(this);
- worker_context->swap_into(this);
- // No body runs that soul anymore at this point, but it is stored in a safe place.
- // When the executed actor will do a blocking action, SIMIX_process_yield() will call suspend(), below.
-}
-
-/** Yield
- *
- * This function is called when a simulated process wants to yield back to the maestro in a blocking simcall,
- * ie in SIMIX_process_yield().
- *
- * Actually, it does not really yield back to maestro, but directly into the next executable actor.
- *
- * This makes the parmap::apply awkward (see ParallelUContext::run_all()) because it only apply regularly
- * on the few first elements of the array, but it saves a lot of context switches back to maestro,
- * and directly forth to the next executable actor.
- */
-void ParallelUContext::suspend()
-{
- // Get some more work to directly swap into the next executable actor instead of yielding back to the parmap
- boost::optional<smx_actor_t> next_work = parmap_->next();
- SwappedContext* next_context;
- if (next_work) {
- // There is a next soul to embody (ie, another executable actor)
- XBT_DEBUG("Run next process");
- next_context = static_cast<ParallelUContext*>(next_work.get()->context_);
- } else {
- // All actors were run, go back to the parmap context
- XBT_DEBUG("No more processes to run");
- // worker_id_ is the identity of my body, stored in thread_local when starting the scheduling round
- next_context = workers_context_[worker_id_];
- // When given that soul, the body will wait for the next scheduling round
- }
-
- // Get the next soul to run, either from another actor or the initial minion's one
- Context::set_current(next_context);
- this->swap_into(next_context);
-}
XBT_PRIVATE ContextFactory* sysv_factory()
{
XBT_VERB("Activating SYSV context factory");
return new UContextFactory();
}
-}}} // namespace simgrid::kernel::context
+} // namespace simgrid::kernel::context
