diff options
Diffstat (limited to 'kernel/sched/ext.c')
| -rw-r--r-- | kernel/sched/ext.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 213793d086d7..89bcca84d6b5 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -8,6 +8,7 @@ enum scx_consts { SCX_DSP_DFL_MAX_BATCH = 32, + SCX_DSP_MAX_LOOPS = 32, SCX_WATCHDOG_MAX_TIMEOUT = 30 * HZ, SCX_EXIT_BT_LEN = 64, @@ -665,6 +666,7 @@ static struct kobject *scx_root_kobj; #define CREATE_TRACE_POINTS #include <trace/events/sched_ext.h> +static void scx_bpf_kick_cpu(s32 cpu, u64 flags); static __printf(3, 4) void scx_ops_exit_kind(enum scx_exit_kind kind, s64 exit_code, const char *fmt, ...); @@ -1906,6 +1908,7 @@ static int balance_scx(struct rq *rq, struct task_struct *prev, { struct scx_dsp_ctx *dspc = this_cpu_ptr(scx_dsp_ctx); bool prev_on_scx = prev->sched_class == &ext_sched_class; + int nr_loops = SCX_DSP_MAX_LOOPS; bool has_tasks = false; lockdep_assert_rq_held(rq); @@ -1962,6 +1965,20 @@ static int balance_scx(struct rq *rq, struct task_struct *prev, goto has_tasks; if (consume_dispatch_q(rq, rf, &scx_dsq_global)) goto has_tasks; + + /* + * ops.dispatch() can trap us in this loop by repeatedly + * dispatching ineligible tasks. Break out once in a while to + * allow the watchdog to run. As IRQ can't be enabled in + * balance(), we want to complete this scheduling cycle and then + * start a new one. IOW, we want to call resched_curr() on the + * next, most likely idle, task, not the current one. Use + * scx_bpf_kick_cpu() for deferred kicking. + */ + if (unlikely(!--nr_loops)) { + scx_bpf_kick_cpu(cpu_of(rq), 0); + break; + } } while (dspc->nr_tasks); goto out; |