From: Tejun Heo <tj@kernel.org> mainline inclusion from mainline-v6.12-rc4 commit aebe7ae4cb50551874fdfaf88e4127884298caad category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ID7HLY Reference: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commi... -------------------------------- Bypass mode was depending on ops.select_cpu() which can't be trusted as with the rest of the BPF scheduler. Always enable and use scx_select_cpu_dfl() in bypass mode. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Vernet <void@manifault.com> Signed-off-by: Zicheng Qu <quzicheng@huawei.com> Signed-off-by: cheliequan <cheliequan@inspur.com> Signed-off-by: Luo Gengkun <luogengkun2@huawei.com> --- kernel/sched/ext.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 7b579cc81e9b..dbac5c707ecf 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -3135,7 +3135,7 @@ static int select_task_rq_scx(struct task_struct *p, int prev_cpu, int wake_flag if (unlikely(wake_flags & WF_EXEC)) return prev_cpu; - if (SCX_HAS_OP(select_cpu)) { + if (SCX_HAS_OP(select_cpu) && !scx_rq_bypassing(task_rq(p))) { s32 cpu; struct task_struct **ddsp_taskp; @@ -3200,7 +3200,7 @@ void __scx_update_idle(struct rq *rq, bool idle) { int cpu = cpu_of(rq); - if (SCX_HAS_OP(update_idle)) { + if (SCX_HAS_OP(update_idle) && !scx_rq_bypassing(rq)) { SCX_CALL_OP(SCX_KF_REST, update_idle, cpu_of(rq), idle); if (!static_branch_unlikely(&scx_builtin_idle_enabled)) return; @@ -4262,21 +4262,23 @@ bool task_should_scx(struct task_struct *p) * the DISABLING state and then cycling the queued tasks through dequeue/enqueue * to force global FIFO scheduling. * - * a. ops.enqueue() is ignored and tasks are queued in simple global FIFO order. - * %SCX_OPS_ENQ_LAST is also ignored. + * - ops.select_cpu() is ignored and the default select_cpu() is used. * - * b. ops.dispatch() is ignored. + * - ops.enqueue() is ignored and tasks are queued in simple global FIFO order. + * %SCX_OPS_ENQ_LAST is also ignored. * - * c. balance_scx() does not set %SCX_RQ_BAL_KEEP on non-zero slice as slice - * can't be trusted. Whenever a tick triggers, the running task is rotated to - * the tail of the queue with core_sched_at touched. + * - ops.dispatch() is ignored. * - * d. pick_next_task() suppresses zero slice warning. + * - balance_scx() does not set %SCX_RQ_BAL_KEEP on non-zero slice as slice + * can't be trusted. Whenever a tick triggers, the running task is rotated to + * the tail of the queue with core_sched_at touched. * - * e. scx_bpf_kick_cpu() is disabled to avoid irq_work malfunction during PM - * operations. + * - pick_next_task() suppresses zero slice warning. * - * f. scx_prio_less() reverts to the default core_sched_at order. + * - scx_bpf_kick_cpu() is disabled to avoid irq_work malfunction during PM + * operations. + * + * - scx_prio_less() reverts to the default core_sched_at order. */ static void scx_ops_bypass(bool bypass) { @@ -4346,7 +4348,7 @@ static void scx_ops_bypass(bool bypass) rq_unlock_irqrestore(rq, &rf); - /* kick to restore ticks */ + /* resched to restore ticks and idle state */ resched_cpu(cpu); } } -- 2.34.1