chromium/base/process/process.h

// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_PROCESS_PROCESS_H_
#define BASE_PROCESS_PROCESS_H_

#include <string_view>

#include "base/base_export.h"
#include "base/process/process_handle.h"
#include "base/time/time.h"
#include "build/blink_buildflags.h"
#include "build/build_config.h"
#include "build/chromeos_buildflags.h"

#if BUILDFLAG(IS_WIN)
#include "base/win/scoped_handle.h"
#endif

#if BUILDFLAG(IS_FUCHSIA)
#include <lib/zx/process.h>
#endif

#if BUILDFLAG(IS_APPLE) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_WIN)
#include "base/feature_list.h"
#endif  // BUILDFLAG(IS_APPLE) || BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_WIN)

#if BUILDFLAG(IS_APPLE)
#include "base/process/port_provider_mac.h"
#endif  // BUILDFLAG(IS_APPLE)

namespace base {

#if BUILDFLAG(IS_CHROMEOS)
// OneGroupPerRenderer feature places each foreground renderer process into
// its own cgroup. This will cause the scheduler to use the aggregate runtime
// of all threads in the process when deciding on the next thread to schedule.
// It will help guarantee fairness between renderers.
BASE_EXPORT BASE_DECLARE_FEATURE(kOneGroupPerRenderer);

// Set all threads of a background process as backgrounded, which changes the
// thread attributes including c-group, latency sensitivity. But the nice value
// is unchanged, since background process is under the spell of the background
// CPU c-group (via cgroup.procs).
BASE_EXPORT BASE_DECLARE_FEATURE(kSetThreadBgForBgProcess);

class ProcessPriorityDelegate;
#endif

#if BUILDFLAG(IS_WIN)
BASE_EXPORT BASE_DECLARE_FEATURE(kUseEcoQoSForBackgroundProcess);

BASE_EXPORT BASE_DECLARE_FEATURE(kEnableIntermediatePriority);
#endif

// Provides a move-only encapsulation of a process.
//
// This object is not tied to the lifetime of the underlying process: the
// process may be killed and this object may still around, and it will still
// claim to be valid. The actual behavior in that case is OS dependent like so:
//
// Windows: The underlying ProcessHandle will be valid after the process dies
// and can be used to gather some information about that process, but most
// methods will obviously fail.
//
// POSIX: The underlying ProcessHandle is not guaranteed to remain valid after
// the process dies, and it may be reused by the system, which means that it may
// end up pointing to the wrong process.
class BASE_EXPORT Process { … };

#if BUILDFLAG(IS_CHROMEOS)
// Exposed for testing.
// Given the contents of the /proc/<pid>/cgroup file, determine whether the
// process is backgrounded or not.
BASE_EXPORT Process::Priority GetProcessPriorityCGroup(
    std::string_view cgroup_contents);
#endif  // BUILDFLAG(IS_CHROMEOS)

}  // namespace base

#endif  // BASE_PROCESS_PROCESS_H_