From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261216AbUKBMZq (ORCPT ); Tue, 2 Nov 2004 07:25:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261210AbUKBMZq (ORCPT ); Tue, 2 Nov 2004 07:25:46 -0500 Received: from smtp208.mail.sc5.yahoo.com ([216.136.130.116]:3506 "HELO smtp208.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S261216AbUKBMZJ (ORCPT ); Tue, 2 Nov 2004 07:25:09 -0500 Message-ID: <41877C9C.7070507@yahoo.com.au> Date: Tue, 02 Nov 2004 23:25:00 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040820 Debian/1.7.2-4 X-Accept-Language: en MIME-Version: 1.0 To: Con Kolivas CC: linux , Andrew Morton , Ingo Molnar Subject: Re: [PATCH] consolidate task preempts References: <418707E2.1060105@kolivas.org> In-Reply-To: <418707E2.1060105@kolivas.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Con Kolivas wrote: > consolidate task preempts > > > > ------------------------------------------------------------------------ > > TASK_PREEMPTS_CURR is only used when followed by resched_task. Consolidate > the two into a single function. > I don't like the name. I actually don't mind the code as it is now; it looks like it gets harder to read, especially with that name. Also, I think you might be better off to leave it inline, as it is just a single comparison. > Allow tasks of equal dynamic priority to preempt tasks of lower static > priority. > Although this change makes the condition more complex. Is it really worth doing? > Signed-off-by: Con Kolivas > > Index: linux-2.6.10-rc1-mm2/kernel/sched.c > =================================================================== > --- linux-2.6.10-rc1-mm2.orig/kernel/sched.c 2004-11-02 14:19:32.973509317 +1100 > +++ linux-2.6.10-rc1-mm2/kernel/sched.c 2004-11-02 14:26:23.444588405 +1100 > @@ -157,9 +157,6 @@ > (JIFFIES_TO_NS(MAX_SLEEP_AVG * \ > (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1)) > > -#define TASK_PREEMPTS_CURR(p, rq) \ > - ((p)->prio < (rq)->curr->prio) > - > /* > * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ] > * to time slice values: [800ms ... 100ms ... 5ms] > @@ -810,6 +807,13 @@ inline int task_curr(const task_t *p) > return cpu_curr(task_cpu(p)) == p; > } > > +static void preempt(task_t *p, runqueue_t *rq) > +{ > + if (p->prio < rq->curr->prio || (p->prio == rq->curr->prio && > + p->static_prio < rq->curr->static_prio)) > + resched_task(rq->curr); > +} > + > #ifdef CONFIG_SMP > enum request_type { > REQ_MOVE_TASK, > @@ -1106,10 +1110,8 @@ out_activate: > * to be considered on this CPU.) > */ > activate_task(p, rq, cpu == this_cpu); > - if (!sync || cpu != this_cpu) { > - if (TASK_PREEMPTS_CURR(p, rq)) > - resched_task(rq->curr); > - } > + if (!sync || cpu != this_cpu) > + preempt(p, rq); > success = 1; > > out_running: > @@ -1263,8 +1265,7 @@ void fastcall wake_up_new_task(task_t * > p->timestamp = (p->timestamp - this_rq->timestamp_last_tick) > + rq->timestamp_last_tick; > __activate_task(p, rq); > - if (TASK_PREEMPTS_CURR(p, rq)) > - resched_task(rq->curr); > + preempt(p, rq); > > schedstat_inc(rq, wunt_moved); > /* > @@ -1621,8 +1622,7 @@ void pull_task(runqueue_t *src_rq, prio_ > * Note that idle threads have a prio of MAX_PRIO, for this test > * to be always true for them. > */ > - if (TASK_PREEMPTS_CURR(p, this_rq)) > - resched_task(this_rq->curr); > + preempt(p, this_rq); > } > > /* > @@ -3306,8 +3306,8 @@ recheck: > if (task_running(rq, p)) { > if (p->prio > oldprio) > resched_task(rq->curr); > - } else if (TASK_PREEMPTS_CURR(p, rq)) > - resched_task(rq->curr); > + } else > + preempt(p, rq); > } > task_rq_unlock(rq, &flags); > out_unlock: > @@ -4008,8 +4008,7 @@ static void __migrate_task(struct task_s > + rq_dest->timestamp_last_tick; > deactivate_task(p, rq_src); > activate_task(p, rq_dest, 0); > - if (TASK_PREEMPTS_CURR(p, rq_dest)) > - resched_task(rq_dest->curr); > + preempt(p, rq_dest); > } > > out: >