Atmosphere/libraries/libmesosphere/include/mesosphere/kern_k_priority_queue.hpp

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/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <mesosphere/kern_common.hpp>
namespace ams::kern {
template<typename T>
concept KPriorityQueueAffinityMask = !std::is_reference<T>::value && requires (T &t) {
{ t.GetAffinityMask() } -> std::convertible_to<u64>;
{ t.SetAffinityMask(std::declval<u64>()) };
{ t.GetAffinity(std::declval<int32_t>()) } -> std::same_as<bool>;
{ t.SetAffinity(std::declval<int32_t>(), std::declval<bool>()) };
{ t.SetAll() };
};
template<typename T>
concept KPriorityQueueMember = !std::is_reference<T>::value && requires (T &t) {
{ typename T::QueueEntry() };
{ (typename T::QueueEntry()).Initialize() };
{ (typename T::QueueEntry()).SetPrev(std::addressof(t)) };
{ (typename T::QueueEntry()).SetNext(std::addressof(t)) };
{ (typename T::QueueEntry()).GetNext() } -> std::same_as<T*>;
{ (typename T::QueueEntry()).GetPrev() } -> std::same_as<T*>;
{ t.GetPriorityQueueEntry(std::declval<s32>()) } -> std::same_as<typename T::QueueEntry &>;
{ t.GetAffinityMask() };
{ typename std::remove_cvref<decltype(t.GetAffinityMask())>::type() } -> KPriorityQueueAffinityMask;
{ t.GetActiveCore() } -> std::convertible_to<s32>;
{ t.GetPriority() } -> std::convertible_to<s32>;
};
template<typename Member, size_t _NumCores, int LowestPriority, int HighestPriority> requires KPriorityQueueMember<Member>
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class KPriorityQueue {
public:
using AffinityMaskType = typename std::remove_cv<typename std::remove_reference<decltype(std::declval<Member>().GetAffinityMask())>::type>::type;
static_assert(LowestPriority >= 0);
static_assert(HighestPriority >= 0);
static_assert(LowestPriority >= HighestPriority);
static constexpr size_t NumPriority = LowestPriority - HighestPriority + 1;
static constexpr size_t NumCores = _NumCores;
static constexpr ALWAYS_INLINE bool IsValidCore(s32 core) {
return 0 <= core && core < static_cast<s32>(NumCores);
}
static constexpr ALWAYS_INLINE bool IsValidPriority(s32 priority) {
return HighestPriority <= priority && priority <= LowestPriority + 1;
}
private:
using Entry = typename Member::QueueEntry;
public:
class KPerCoreQueue {
private:
Entry root[NumCores];
public:
constexpr ALWAYS_INLINE KPerCoreQueue() : root() {
for (size_t i = 0; i < NumCores; i++) {
this->root[i].Initialize();
}
}
constexpr ALWAYS_INLINE bool PushBack(s32 core, Member *member) {
/* Get the entry associated with the member. */
Entry &member_entry = member->GetPriorityQueueEntry(core);
/* Get the entry associated with the end of the queue. */
Member *tail = this->root[core].GetPrev();
Entry &tail_entry = (tail != nullptr) ? tail->GetPriorityQueueEntry(core) : this->root[core];
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/* Link the entries. */
member_entry.SetPrev(tail);
member_entry.SetNext(nullptr);
tail_entry.SetNext(member);
this->root[core].SetPrev(member);
return (tail == nullptr);
}
constexpr ALWAYS_INLINE bool PushFront(s32 core, Member *member) {
/* Get the entry associated with the member. */
Entry &member_entry = member->GetPriorityQueueEntry(core);
/* Get the entry associated with the front of the queue. */
Member *head = this->root[core].GetNext();
Entry &head_entry = (head != nullptr) ? head->GetPriorityQueueEntry(core) : this->root[core];
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/* Link the entries. */
member_entry.SetPrev(nullptr);
member_entry.SetNext(head);
head_entry.SetPrev(member);
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this->root[core].SetNext(member);
return (head == nullptr);
}
constexpr ALWAYS_INLINE bool Remove(s32 core, Member *member) {
/* Get the entry associated with the member. */
Entry &member_entry = member->GetPriorityQueueEntry(core);
/* Get the entries associated with next and prev. */
Member *prev = member_entry.GetPrev();
Member *next = member_entry.GetNext();
Entry &prev_entry = (prev != nullptr) ? prev->GetPriorityQueueEntry(core) : this->root[core];
Entry &next_entry = (next != nullptr) ? next->GetPriorityQueueEntry(core) : this->root[core];
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/* Unlink. */
prev_entry.SetNext(next);
next_entry.SetPrev(prev);
return (this->GetFront(core) == nullptr);
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}
constexpr ALWAYS_INLINE Member *GetFront(s32 core) const {
return this->root[core].GetNext();
}
};
class KPriorityQueueImpl {
private:
KPerCoreQueue queues[NumPriority];
util::BitSet64<NumPriority> available_priorities[NumCores];
public:
constexpr ALWAYS_INLINE KPriorityQueueImpl() : queues(), available_priorities() { /* ... */ }
constexpr ALWAYS_INLINE void PushBack(s32 priority, s32 core, Member *member) {
MESOSPHERE_ASSERT(IsValidCore(core));
MESOSPHERE_ASSERT(IsValidPriority(priority));
if (AMS_LIKELY(priority <= LowestPriority)) {
if (this->queues[priority].PushBack(core, member)) {
this->available_priorities[core].SetBit(priority);
}
}
}
constexpr ALWAYS_INLINE void PushFront(s32 priority, s32 core, Member *member) {
MESOSPHERE_ASSERT(IsValidCore(core));
MESOSPHERE_ASSERT(IsValidPriority(priority));
if (AMS_LIKELY(priority <= LowestPriority)) {
if (this->queues[priority].PushFront(core, member)) {
this->available_priorities[core].SetBit(priority);
}
}
}
constexpr ALWAYS_INLINE void Remove(s32 priority, s32 core, Member *member) {
MESOSPHERE_ASSERT(IsValidCore(core));
MESOSPHERE_ASSERT(IsValidPriority(priority));
if (AMS_LIKELY(priority <= LowestPriority)) {
if (this->queues[priority].Remove(core, member)) {
this->available_priorities[core].ClearBit(priority);
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}
}
}
constexpr ALWAYS_INLINE Member *GetFront(s32 core) const {
MESOSPHERE_ASSERT(IsValidCore(core));
const s32 priority = this->available_priorities[core].CountLeadingZero();
if (AMS_LIKELY(priority <= LowestPriority)) {
return this->queues[priority].GetFront(core);
} else {
return nullptr;
}
}
constexpr ALWAYS_INLINE Member *GetFront(s32 priority, s32 core) const {
MESOSPHERE_ASSERT(IsValidCore(core));
MESOSPHERE_ASSERT(IsValidPriority(priority));
if (AMS_LIKELY(priority <= LowestPriority)) {
return this->queues[priority].GetFront(core);
} else {
return nullptr;
}
}
constexpr ALWAYS_INLINE Member *GetNext(s32 core, const Member *member) const {
MESOSPHERE_ASSERT(IsValidCore(core));
Member *next = member->GetPriorityQueueEntry(core).GetNext();
if (next == nullptr) {
const s32 priority = this->available_priorities[core].GetNextSet(member->GetPriority());
if (AMS_LIKELY(priority <= LowestPriority)) {
next = this->queues[priority].GetFront(core);
}
}
return next;
}
constexpr ALWAYS_INLINE void MoveToFront(s32 priority, s32 core, Member *member) {
MESOSPHERE_ASSERT(IsValidCore(core));
MESOSPHERE_ASSERT(IsValidPriority(priority));
if (AMS_LIKELY(priority <= LowestPriority)) {
this->queues[priority].Remove(core, member);
this->queues[priority].PushFront(core, member);
}
}
constexpr ALWAYS_INLINE Member *MoveToBack(s32 priority, s32 core, Member *member) {
MESOSPHERE_ASSERT(IsValidCore(core));
MESOSPHERE_ASSERT(IsValidPriority(priority));
if (AMS_LIKELY(priority <= LowestPriority)) {
this->queues[priority].Remove(core, member);
this->queues[priority].PushBack(core, member);
return this->queues[priority].GetFront(core);
} else {
return nullptr;
}
}
};
private:
KPriorityQueueImpl scheduled_queue;
KPriorityQueueImpl suggested_queue;
private:
constexpr ALWAYS_INLINE void ClearAffinityBit(u64 &affinity, s32 core) {
affinity &= ~(u64(1ul) << core);
}
constexpr ALWAYS_INLINE s32 GetNextCore(u64 &affinity) {
const s32 core = __builtin_ctzll(static_cast<unsigned long long>(affinity));
ClearAffinityBit(affinity, core);
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return core;
}
constexpr ALWAYS_INLINE void PushBack(s32 priority, Member *member) {
MESOSPHERE_ASSERT(IsValidPriority(priority));
/* Push onto the scheduled queue for its core, if we can. */
u64 affinity = member->GetAffinityMask().GetAffinityMask();
if (const s32 core = member->GetActiveCore(); core >= 0) {
this->scheduled_queue.PushBack(priority, core, member);
ClearAffinityBit(affinity, core);
}
/* And suggest the thread for all other cores. */
while (affinity) {
this->suggested_queue.PushBack(priority, GetNextCore(affinity), member);
}
}
constexpr ALWAYS_INLINE void PushFront(s32 priority, Member *member) {
MESOSPHERE_ASSERT(IsValidPriority(priority));
/* Push onto the scheduled queue for its core, if we can. */
u64 affinity = member->GetAffinityMask().GetAffinityMask();
if (const s32 core = member->GetActiveCore(); core >= 0) {
this->scheduled_queue.PushFront(priority, core, member);
ClearAffinityBit(affinity, core);
}
/* And suggest the thread for all other cores. */
/* Note: Nintendo pushes onto the back of the suggested queue, not the front. */
while (affinity) {
this->suggested_queue.PushBack(priority, GetNextCore(affinity), member);
}
}
constexpr ALWAYS_INLINE void Remove(s32 priority, Member *member) {
MESOSPHERE_ASSERT(IsValidPriority(priority));
/* Remove from the scheduled queue for its core. */
u64 affinity = member->GetAffinityMask().GetAffinityMask();
if (const s32 core = member->GetActiveCore(); core >= 0) {
this->scheduled_queue.Remove(priority, core, member);
ClearAffinityBit(affinity, core);
}
/* Remove from the suggested queue for all other cores. */
while (affinity) {
this->suggested_queue.Remove(priority, GetNextCore(affinity), member);
}
}
public:
constexpr ALWAYS_INLINE KPriorityQueue() : scheduled_queue(), suggested_queue() { /* ... */ }
/* Getters. */
constexpr ALWAYS_INLINE Member *GetScheduledFront(s32 core) const {
return this->scheduled_queue.GetFront(core);
}
constexpr ALWAYS_INLINE Member *GetScheduledFront(s32 core, s32 priority) const {
return this->scheduled_queue.GetFront(priority, core);
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}
constexpr ALWAYS_INLINE Member *GetSuggestedFront(s32 core) const {
return this->suggested_queue.GetFront(core);
}
constexpr ALWAYS_INLINE Member *GetSuggestedFront(s32 core, s32 priority) const {
return this->suggested_queue.GetFront(priority, core);
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}
constexpr ALWAYS_INLINE Member *GetScheduledNext(s32 core, const Member *member) const {
return this->scheduled_queue.GetNext(core, member);
}
constexpr ALWAYS_INLINE Member *GetSuggestedNext(s32 core, const Member *member) const {
return this->suggested_queue.GetNext(core, member);
}
constexpr ALWAYS_INLINE Member *GetSamePriorityNext(s32 core, const Member *member) const {
return member->GetPriorityQueueEntry(core).GetNext();
}
/* Mutators. */
constexpr ALWAYS_INLINE void PushBack(Member *member) {
this->PushBack(member->GetPriority(), member);
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}
constexpr ALWAYS_INLINE void Remove(Member *member) {
this->Remove(member->GetPriority(), member);
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}
constexpr ALWAYS_INLINE void MoveToScheduledFront(Member *member) {
this->scheduled_queue.MoveToFront(member->GetPriority(), member->GetActiveCore(), member);
}
constexpr ALWAYS_INLINE KThread *MoveToScheduledBack(Member *member) {
return this->scheduled_queue.MoveToBack(member->GetPriority(), member->GetActiveCore(), member);
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}
/* First class fancy operations. */
constexpr ALWAYS_INLINE void ChangePriority(s32 prev_priority, bool is_running, Member *member) {
MESOSPHERE_ASSERT(IsValidPriority(prev_priority));
/* Remove the member from the queues. */
const s32 new_priority = member->GetPriority();
this->Remove(prev_priority, member);
/* And enqueue. If the member is running, we want to keep it running. */
if (is_running) {
this->PushFront(new_priority, member);
} else {
this->PushBack(new_priority, member);
}
}
constexpr ALWAYS_INLINE void ChangeAffinityMask(s32 prev_core, const AffinityMaskType &prev_affinity, Member *member) {
/* Get the new information. */
const s32 priority = member->GetPriority();
const AffinityMaskType &new_affinity = member->GetAffinityMask();
const s32 new_core = member->GetActiveCore();
/* Remove the member from all queues it was in before. */
for (s32 core = 0; core < static_cast<s32>(NumCores); core++) {
if (prev_affinity.GetAffinity(core)) {
if (core == prev_core) {
this->scheduled_queue.Remove(priority, core, member);
} else {
this->suggested_queue.Remove(priority, core, member);
}
}
}
/* And add the member to all queues it should be in now. */
for (s32 core = 0; core < static_cast<s32>(NumCores); core++) {
if (new_affinity.GetAffinity(core)) {
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if (core == new_core) {
this->scheduled_queue.PushBack(priority, core, member);
} else {
this->suggested_queue.PushBack(priority, core, member);
}
}
}
}
constexpr ALWAYS_INLINE void ChangeCore(s32 prev_core, Member *member, bool to_front = false) {
/* Get the new information. */
const s32 new_core = member->GetActiveCore();
const s32 priority = member->GetPriority();
/* We don't need to do anything if the core is the same. */
if (prev_core != new_core) {
/* Remove from the scheduled queue for the previous core. */
if (prev_core >= 0) {
this->scheduled_queue.Remove(priority, prev_core, member);
}
/* Remove from the suggested queue and add to the scheduled queue for the new core. */
if (new_core >= 0) {
this->suggested_queue.Remove(priority, prev_core, member);
if (to_front) {
this->scheduled_queue.PushFront(priority, new_core, member);
} else {
this->scheduled_queue.PushBack(priority, new_core, member);
}
}
/* Add to the suggested queue for the previous core. */
if (prev_core >= 0) {
this->suggested_queue.PushBack(priority, prev_core, member);
}
}
}
};
}