From: Tejun Heo <tj@kernel.org> mainline inclusion from mainline-v6.12-rc1 commit c9c809f4137c3c0f962226c10d245d3ce2fd5b7c category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IDC9YK Reference: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commi... -------------------------------- scx_flatcg was using SCX_DSQ_GLOBAL for fallback handling. However, it is assuming that SCX_DSQ_GLOBAL isn't automatically consumed, which was true a while ago but is no longer the case. Also, there are further changes planned for SCX_DSQ_GLOBAL which will disallow explicit consumption from it. Switch to a user DSQ for fallback. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Vernet <void@manifault.com> Signed-off-by: Zicheng Qu <quzicheng@huawei.com> --- tools/sched_ext/scx_flatcg.bpf.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/tools/sched_ext/scx_flatcg.bpf.c b/tools/sched_ext/scx_flatcg.bpf.c index e272bc39bbbd..b722baf6da4b 100644 --- a/tools/sched_ext/scx_flatcg.bpf.c +++ b/tools/sched_ext/scx_flatcg.bpf.c @@ -49,7 +49,10 @@ /* * Maximum amount of retries to find a valid cgroup. */ -#define CGROUP_MAX_RETRIES 1024 +enum { + FALLBACK_DSQ = 0, + CGROUP_MAX_RETRIES = 1024, +}; char _license[] SEC("license") = "GPL"; @@ -377,7 +380,7 @@ void BPF_STRUCT_OPS(fcg_enqueue, struct task_struct *p, u64 enq_flags) scx_bpf_dispatch(p, SCX_DSQ_LOCAL, SCX_SLICE_DFL, enq_flags); } else { stat_inc(FCG_STAT_GLOBAL); - scx_bpf_dispatch(p, SCX_DSQ_GLOBAL, SCX_SLICE_DFL, enq_flags); + scx_bpf_dispatch(p, FALLBACK_DSQ, SCX_SLICE_DFL, enq_flags); } return; } @@ -780,7 +783,7 @@ void BPF_STRUCT_OPS(fcg_dispatch, s32 cpu, struct task_struct *prev) pick_next_cgroup: cpuc->cur_at = now; - if (scx_bpf_consume(SCX_DSQ_GLOBAL)) { + if (scx_bpf_consume(FALLBACK_DSQ)) { cpuc->cur_cgid = 0; return; } @@ -837,7 +840,7 @@ int BPF_STRUCT_OPS_SLEEPABLE(fcg_cgroup_init, struct cgroup *cgrp, int ret; /* - * Technically incorrect as cgroup ID is full 64bit while dq ID is + * Technically incorrect as cgroup ID is full 64bit while dsq ID is * 63bit. Should not be a problem in practice and easy to spot in the * unlikely case that it breaks. */ @@ -925,6 +928,11 @@ void BPF_STRUCT_OPS(fcg_cgroup_move, struct task_struct *p, p->scx.dsq_vtime = to_cgc->tvtime_now + vtime_delta; } +s32 BPF_STRUCT_OPS_SLEEPABLE(fcg_init) +{ + return scx_bpf_create_dsq(FALLBACK_DSQ, -1); +} + void BPF_STRUCT_OPS(fcg_exit, struct scx_exit_info *ei) { UEI_RECORD(uei, ei); @@ -943,6 +951,7 @@ SCX_OPS_DEFINE(flatcg_ops, .cgroup_init = (void *)fcg_cgroup_init, .cgroup_exit = (void *)fcg_cgroup_exit, .cgroup_move = (void *)fcg_cgroup_move, + .init = (void *)fcg_init, .exit = (void *)fcg_exit, .flags = SCX_OPS_HAS_CGROUP_WEIGHT | SCX_OPS_ENQ_EXITING, .name = "flatcg"); -- 2.34.1