diff options
Diffstat (limited to 'kernel/sched/ext/internal.h')
| -rw-r--r-- | kernel/sched/ext/internal.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/kernel/sched/ext/internal.h b/kernel/sched/ext/internal.h index 1f5312b3b387..145272cb4d8a 100644 --- a/kernel/sched/ext/internal.h +++ b/kernel/sched/ext/internal.h @@ -1553,6 +1553,111 @@ static inline struct rq *scx_locked_rq(void) return __this_cpu_read(scx_locked_rq_state); } +static inline void update_locked_rq(struct rq *rq) +{ + /* + * Check whether @rq is actually locked. This can help expose bugs + * or incorrect assumptions about the context in which a kfunc or + * callback is executed. + */ + if (rq) + lockdep_assert_rq_held(rq); + __this_cpu_write(scx_locked_rq_state, rq); +} + +#define SCX_HAS_OP(sch, op) test_bit(SCX_OP_IDX(op), (sch)->has_op) + +/* + * SCX ops can recurse via scx_bpf_sub_dispatch() - the inner call must not + * clobber the outer's scx_locked_rq_state. Save it on entry, restore on exit. + */ +#define SCX_CALL_OP(sch, op, locked_rq, args...) \ +do { \ + struct rq *__prev_locked_rq; \ + \ + if (locked_rq) { \ + __prev_locked_rq = scx_locked_rq(); \ + update_locked_rq(locked_rq); \ + } \ + (sch)->ops.op(args); \ + if (locked_rq) \ + update_locked_rq(__prev_locked_rq); \ +} while (0) + +#define SCX_CALL_OP_RET(sch, op, locked_rq, args...) \ +({ \ + struct rq *__prev_locked_rq; \ + __typeof__((sch)->ops.op(args)) __ret; \ + \ + if (locked_rq) { \ + __prev_locked_rq = scx_locked_rq(); \ + update_locked_rq(locked_rq); \ + } \ + __ret = (sch)->ops.op(args); \ + if (locked_rq) \ + update_locked_rq(__prev_locked_rq); \ + __ret; \ +}) + +/* + * SCX_CALL_OP_TASK*() invokes an SCX op that takes one or two task arguments + * and records them in current->scx.kf_tasks[] for the duration of the call. A + * kfunc invoked from inside such an op can then use + * scx_kf_arg_task_ok() to verify that its task argument is one of + * those subject tasks. + * + * Every SCX_CALL_OP_TASK*() call site invokes its op with @p's rq lock held - + * either via the @locked_rq argument here, or (for ops.select_cpu()) via @p's + * pi_lock held by try_to_wake_up() with rq tracking via scx_rq.in_select_cpu. + * So if kf_tasks[] is set, @p's scheduler-protected fields are stable. + * + * kf_tasks[] can not stack, so task-based SCX ops must not nest. The + * WARN_ON_ONCE() in each macro catches a re-entry of any of the three variants + * while a previous one is still in progress. + */ +#define SCX_CALL_OP_TASK(sch, op, locked_rq, task, args...) \ +do { \ + WARN_ON_ONCE(current->scx.kf_tasks[0]); \ + current->scx.kf_tasks[0] = task; \ + SCX_CALL_OP((sch), op, locked_rq, task, ##args); \ + current->scx.kf_tasks[0] = NULL; \ +} while (0) + +#define SCX_CALL_OP_TASK_RET(sch, op, locked_rq, task, args...) \ +({ \ + __typeof__((sch)->ops.op(task, ##args)) __ret; \ + WARN_ON_ONCE(current->scx.kf_tasks[0]); \ + current->scx.kf_tasks[0] = task; \ + __ret = SCX_CALL_OP_RET((sch), op, locked_rq, task, ##args); \ + current->scx.kf_tasks[0] = NULL; \ + __ret; \ +}) + +#define SCX_CALL_OP_2TASKS_RET(sch, op, locked_rq, task0, task1, args...) \ +({ \ + __typeof__((sch)->ops.op(task0, task1, ##args)) __ret; \ + WARN_ON_ONCE(current->scx.kf_tasks[0]); \ + current->scx.kf_tasks[0] = task0; \ + current->scx.kf_tasks[1] = task1; \ + __ret = SCX_CALL_OP_RET((sch), op, locked_rq, task0, task1, ##args); \ + current->scx.kf_tasks[0] = NULL; \ + current->scx.kf_tasks[1] = NULL; \ + __ret; \ +}) + +/* see SCX_CALL_OP_TASK() */ +static __always_inline bool scx_kf_arg_task_ok(struct scx_sched *sch, + struct task_struct *p) +{ + if (unlikely((p != current->scx.kf_tasks[0] && + p != current->scx.kf_tasks[1]))) { + scx_error(sch, "called on a task not being operated on"); + return false; + } + + return true; +} + static inline bool scx_bypassing(struct scx_sched *sch, s32 cpu) { return unlikely(per_cpu_ptr(sch->pcpu, cpu)->flags & @@ -1633,6 +1738,20 @@ static inline struct scx_sched *scx_prog_sched(const struct bpf_prog_aux *aux) return NULL; } + +/** + * scx_parent - Find the parent sched + * @sch: sched to find the parent of + * + * Returns the parent scheduler or %NULL if @sch is root. + */ +static inline struct scx_sched *scx_parent(struct scx_sched *sch) +{ + if (sch->level) + return sch->ancestors[sch->level - 1]; + else + return NULL; +} #else /* CONFIG_EXT_SUB_SCHED */ static inline struct scx_sched *scx_task_sched(const struct task_struct *p) { @@ -1656,6 +1775,8 @@ static inline struct scx_sched *scx_prog_sched(const struct bpf_prog_aux *aux) { return rcu_dereference_all(scx_root); } + +static inline struct scx_sched *scx_parent(struct scx_sched *sch) { return NULL; } #endif /* CONFIG_EXT_SUB_SCHED */ #endif /* _KERNEL_SCHED_EXT_INTERNAL_H */ |