From ce897abc21b2d5e74981ff2b848f3a08a580d50a Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sat, 7 Mar 2026 05:29:50 -1000 Subject: sched_ext: Add SCX_TASK_REENQ_REASON flags SCX_ENQ_REENQ indicates that a task is being re-enqueued but doesn't tell the BPF scheduler why. Add SCX_TASK_REENQ_REASON flags using bits 12-13 of p->scx.flags to communicate the reason during ops.enqueue(): - NONE: Not being reenqueued - KFUNC: Reenqueued by scx_bpf_dsq_reenq() and friends More reasons will be added. Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- include/linux/sched/ext.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/linux/sched') diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h index e822b374b17f..60a4f65d0174 100644 --- a/include/linux/sched/ext.h +++ b/include/linux/sched/ext.h @@ -118,6 +118,21 @@ enum scx_ent_flags { SCX_TASK_READY = 2 << SCX_TASK_STATE_SHIFT, SCX_TASK_ENABLED = 3 << SCX_TASK_STATE_SHIFT, + /* + * Bits 12 and 13 are used to carry reenqueue reason. In addition to + * %SCX_ENQ_REENQ flag, ops.enqueue() can also test for + * %SCX_TASK_REENQ_REASON_NONE to distinguish reenqueues. + * + * NONE not being reenqueued + * KFUNC reenqueued by scx_bpf_dsq_reenq() and friends + */ + SCX_TASK_REENQ_REASON_SHIFT = 12, + SCX_TASK_REENQ_REASON_BITS = 2, + SCX_TASK_REENQ_REASON_MASK = ((1 << SCX_TASK_REENQ_REASON_BITS) - 1) << SCX_TASK_REENQ_REASON_SHIFT, + + SCX_TASK_REENQ_NONE = 0 << SCX_TASK_REENQ_REASON_SHIFT, + SCX_TASK_REENQ_KFUNC = 1 << SCX_TASK_REENQ_REASON_SHIFT, + /* iteration cursor, not a task */ SCX_TASK_CURSOR = 1 << 31, }; -- cgit v1.2.3