From d4af01c3731ff9c6e224d7183f8226a56d72b56c Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 8 Jul 2024 14:30:55 -1000 Subject: sched_ext: Take out ->priq and ->flags from scx_dsq_node struct scx_dsq_node contains two data structure nodes to link the containing task to a DSQ and a flags field that is protected by the lock of the associated DSQ. One reason why they are grouped into a struct is to use the type independently as a cursor node when iterating tasks on a DSQ. However, when iterating, the cursor only needs to be linked on the FIFO list and the rb_node part ends up inflating the size of the iterator data structure unnecessarily making it potentially too expensive to place it on stack. Take ->priq and ->flags out of scx_dsq_node and put them in sched_ext_entity as ->dsq_priq and ->dsq_flags, respectively. scx_dsq_node is renamed to scx_dsq_list_node and the field names are renamed accordingly. This will help implementing DSQ task iterator that can be allocated on stack. No functional change intended. Signed-off-by: Tejun Heo Suggested-by: Alexei Starovoitov Acked-by: Alexei Starovoitov Cc: David Vernet --- include/linux/sched/ext.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h index fe9a67ffe6b1..eb9cfd18a923 100644 --- a/include/linux/sched/ext.h +++ b/include/linux/sched/ext.h @@ -121,10 +121,8 @@ enum scx_kf_mask { __SCX_KF_TERMINAL = SCX_KF_ENQUEUE | SCX_KF_SELECT_CPU | SCX_KF_REST, }; -struct scx_dsq_node { - struct list_head list; /* dispatch order */ - struct rb_node priq; /* p->scx.dsq_vtime order */ - u32 flags; /* SCX_TASK_DSQ_* flags */ +struct scx_dsq_list_node { + struct list_head node; }; /* @@ -133,7 +131,9 @@ struct scx_dsq_node { */ struct sched_ext_entity { struct scx_dispatch_q *dsq; - struct scx_dsq_node dsq_node; /* protected by dsq lock */ + struct scx_dsq_list_node dsq_list; /* dispatch order */ + struct rb_node dsq_priq; /* p->scx.dsq_vtime order */ + u32 dsq_flags; /* protected by DSQ lock */ u32 flags; /* protected by rq lock */ u32 weight; s32 sticky_cpu; -- cgit v1.3.1