Re: [RFC][PATCH 17/22] sched: add signaling overrunning -deadlinetasks.

From: Peter Zijlstra
Date: Thu Nov 11 2010 - 16:58:34 EST


On Fri, 2010-10-29 at 08:40 +0200, Raistlin wrote:
> +static inline void __dl_signal(struct task_struct *tsk, int which)
> +{
> + struct siginfo info;
> + long long amount = which == SF_SIG_DMISS ? tsk->dl.stats.last_dmiss :
> + tsk->dl.stats.last_rorun;
> +
> + info.si_signo = SIGXCPU;
> + info.si_errno = which;
> + info.si_code = SI_KERNEL;
> + info.si_pid = 0;
> + info.si_uid = 0;
> + info.si_value.sival_int = (int)amount;
> +
> + /* Correctly take the locks on task's sighand */
> + __group_send_sig_info(SIGXCPU, &info, tsk);
> + /* Log what happened to dmesg */
> + printk(KERN_INFO "SCHED_DEADLINE: 0x%4x by %Ld [ns] in %d (%s)\n",
> + which, amount, task_pid_nr(tsk), tsk->comm);
> +}

This being a G-EDF like scheduler with a u<=1 schedulability test, we're
firmly in soft-rt territory which means the above will be very easy to
trigger.. Maybe not spam dmesg?
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