mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-09-20 09:49:15 +03:00
1d621ab172
This adds support for FUTEX_WAKE_OP, FUTEX_WAIT_BITSET, FUTEX_WAKE_BITSET, FUTEX_REQUEUE, and FUTEX_CMP_REQUEUE, as well well as global and private futex and absolute/relative timeouts against the appropriate clock. This also changes the implementation so that kernel resources are only used when a thread is blocked on a futex. Global futexes are implemented as offsets in VMObjects, so that different processes can share a futex against the same VMObject despite potentially being mapped at different virtual addresses.
127 lines
4.4 KiB
C++
127 lines
4.4 KiB
C++
/*
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* Copyright (c) 2020, The SerenityOS developers.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <Kernel/Thread.h>
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#include <Kernel/WaitQueue.h>
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//#define WAITQUEUE_DEBUG
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namespace Kernel {
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bool WaitQueue::should_add_blocker(Thread::Blocker& b, void* data)
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{
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ASSERT(data != nullptr); // Thread that is requesting to be blocked
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ASSERT(m_lock.is_locked());
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ASSERT(b.blocker_type() == Thread::Blocker::Type::Queue);
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if (m_wake_requested) {
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m_wake_requested = false;
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#ifdef WAITQUEUE_DEBUG
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dbg() << "WaitQueue @ " << this << ": do not block thread " << *static_cast<Thread*>(data) << ", wake was pending";
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#endif
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return false;
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}
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#ifdef WAITQUEUE_DEBUG
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dbg() << "WaitQueue @ " << this << ": should block thread " << *static_cast<Thread*>(data);
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#endif
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return true;
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}
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void WaitQueue::wake_one()
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{
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ScopedSpinLock lock(m_lock);
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#ifdef WAITQUEUE_DEBUG
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dbg() << "WaitQueue @ " << this << ": wake_one";
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#endif
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bool did_unblock_one = do_unblock([&](Thread::Blocker& b, void* data, bool& stop_iterating) {
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ASSERT(data);
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ASSERT(b.blocker_type() == Thread::Blocker::Type::Queue);
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auto& blocker = static_cast<Thread::QueueBlocker&>(b);
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#ifdef WAITQUEUE_DEBUG
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dbg() << "WaitQueue @ " << this << ": wake_one unblocking " << *static_cast<Thread*>(data);
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#endif
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if (blocker.unblock()) {
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stop_iterating = true;
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return true;
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}
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return false;
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});
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m_wake_requested = !did_unblock_one;
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}
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u32 WaitQueue::wake_n(u32 wake_count)
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{
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if (wake_count == 0)
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return 0; // should we assert instaed?
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ScopedSpinLock lock(m_lock);
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#ifdef WAITQUEUE_DEBUG
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dbg() << "WaitQueue @ " << this << ": wake_n(" << wake_count << ")";
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#endif
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u32 did_wake = 0;
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bool did_unblock_some = do_unblock([&](Thread::Blocker& b, void* data, bool& stop_iterating) {
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ASSERT(data);
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ASSERT(b.blocker_type() == Thread::Blocker::Type::Queue);
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auto& blocker = static_cast<Thread::QueueBlocker&>(b);
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#ifdef WAITQUEUE_DEBUG
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dbg() << "WaitQueue @ " << this << ": wake_n unblocking " << *static_cast<Thread*>(data);
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#endif
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ASSERT(did_wake < wake_count);
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if (blocker.unblock()) {
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if (++did_wake >= wake_count)
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stop_iterating = true;
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return true;
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}
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return false;
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});
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m_wake_requested = !did_unblock_some;
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return did_wake;
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}
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u32 WaitQueue::wake_all()
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{
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ScopedSpinLock lock(m_lock);
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#ifdef WAITQUEUE_DEBUG
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dbg() << "WaitQueue @ " << this << ": wake_all";
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#endif
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u32 did_wake = 0;
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bool did_unblock_any = do_unblock([&](Thread::Blocker& b, void* data, bool&) {
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ASSERT(data);
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ASSERT(b.blocker_type() == Thread::Blocker::Type::Queue);
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auto& blocker = static_cast<Thread::QueueBlocker&>(b);
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#ifdef WAITQUEUE_DEBUG
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dbg() << "WaitQueue @ " << this << ": wake_all unblocking " << *static_cast<Thread*>(data);
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#endif
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if (blocker.unblock()) {
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did_wake++;
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return true;
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}
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return false;
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});
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m_wake_requested = !did_unblock_any;
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return did_wake;
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}
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}
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