ladybird/Kernel/ProcessGroup.h
Brian Gianforcaro e95eb7a51d Kernel: Avoid allocating under spinlock in ProcessGroup::find_or_create
Avoid allocating while holding the g_process_groups_lock spinlock, it's
a pattern that has a negative effect on performance and scalability,
especially given that it is a global lock, reachable by all processes.
2021-05-20 08:10:07 +02:00

54 lines
1.2 KiB
C++

/*
* Copyright (c) 2020, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/InlineLinkedList.h>
#include <AK/RefCounted.h>
#include <AK/Weakable.h>
#include <Kernel/Lock.h>
#include <Kernel/SpinLock.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
class ProcessGroup
: public RefCounted<ProcessGroup>
, public Weakable<ProcessGroup>
, public InlineLinkedListNode<ProcessGroup> {
AK_MAKE_NONMOVABLE(ProcessGroup);
AK_MAKE_NONCOPYABLE(ProcessGroup);
friend InlineLinkedListNode<ProcessGroup>;
public:
~ProcessGroup();
static RefPtr<ProcessGroup> create(ProcessGroupID);
static RefPtr<ProcessGroup> find_or_create(ProcessGroupID);
static RefPtr<ProcessGroup> from_pgid(ProcessGroupID);
const ProcessGroupID& pgid() const { return m_pgid; }
private:
ProcessGroup(ProcessGroupID pgid)
: m_pgid(pgid)
{
}
static RefPtr<ProcessGroup> from_pgid_nolock(ProcessGroupID);
ProcessGroup* m_prev { nullptr };
ProcessGroup* m_next { nullptr };
ProcessGroupID m_pgid;
};
extern InlineLinkedList<ProcessGroup>* g_process_groups;
extern RecursiveSpinLock g_process_groups_lock;
}