Alice Ryhl
7163533526
The 6.12.19 LTS of the kernel contains some changes to the Rust kernel crate involving the integer types used for FFI and the removal of the alloc crate in favor of a custom alloc utilities. Bug: 388786466 Change-Id: Ie4cab650deaf1f2ffc4ee64d367e52f0671791c1 Signed-off-by: Alice Ryhl <aliceryhl@google.com>
81 lines
2.2 KiB
Rust
81 lines
2.2 KiB
Rust
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2024 Google LLC.
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//! This module defines the types and methods relevant to priority inheritance.
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use kernel::bindings;
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pub(crate) type Policy = kernel::ffi::c_uint;
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pub(crate) type Priority = kernel::ffi::c_int;
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pub(crate) type Nice = kernel::ffi::c_int;
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pub(crate) const SCHED_NORMAL: Policy = bindings::SCHED_NORMAL;
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pub(crate) const SCHED_FIFO: Policy = bindings::SCHED_FIFO;
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pub(crate) const MIN_NICE: Nice = bindings::MIN_NICE as _;
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pub(crate) const MAX_NICE: Nice = bindings::MAX_NICE as _;
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pub(crate) const DEFAULT_PRIO: Priority = bindings::DEFAULT_PRIO as _;
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pub(crate) const MAX_RT_PRIO: Priority = bindings::MAX_RT_PRIO as _;
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/// Scheduler policy and priority.
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///
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/// The binder driver supports inheriting the following scheduler policies:
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/// * SCHED_NORMAL
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/// * SCHED_BATCH
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/// * SCHED_FIFO
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/// * SCHED_RR
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#[derive(Copy, Clone, Default)]
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pub(crate) struct BinderPriority {
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pub(crate) sched_policy: Policy,
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pub(crate) prio: Priority,
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}
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#[derive(Copy, Clone, Eq, PartialEq)]
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pub(crate) enum PriorityState {
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Set,
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Pending,
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Abort,
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}
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pub(crate) fn get_default_prio_from_task(task: &kernel::task::Task) -> BinderPriority {
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if is_supported_policy(task.policy()) {
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BinderPriority {
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sched_policy: task.policy(),
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prio: task.normal_prio(),
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}
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} else {
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BinderPriority {
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sched_policy: SCHED_NORMAL,
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prio: DEFAULT_PRIO,
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}
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}
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}
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pub(crate) fn is_rt_policy(policy: Policy) -> bool {
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policy == bindings::SCHED_FIFO || policy == bindings::SCHED_RR
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}
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pub(crate) fn is_fair_policy(policy: Policy) -> bool {
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policy == bindings::SCHED_NORMAL || policy == bindings::SCHED_BATCH
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}
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pub(crate) fn is_supported_policy(policy: Policy) -> bool {
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is_fair_policy(policy) || is_rt_policy(policy)
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}
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pub(crate) fn to_userspace_prio(policy: Policy, prio: Priority) -> Nice {
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if is_fair_policy(policy) {
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prio - DEFAULT_PRIO
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} else {
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MAX_RT_PRIO - 1 - prio
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}
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}
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pub(crate) fn to_kernel_prio(policy: Policy, prio: Nice) -> Priority {
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if is_fair_policy(policy) {
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prio + DEFAULT_PRIO
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} else {
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MAX_RT_PRIO - 1 - prio
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}
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}
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