Commit 9d061ba6 authored by Dietmar Eggemann's avatar Dietmar Eggemann Committed by Ingo Molnar
Browse files

sched: Remove USER_PRIO, TASK_USER_PRIO and MAX_USER_PRIO 



The only remaining use of MAX_USER_PRIO (and USER_PRIO) is the
SCALE_PRIO() definition in the PowerPC Cell architecture's Synergistic
Processor Unit (SPU) scheduler. TASK_USER_PRIO isn't used anymore.

Commit fe443ef2 ("[POWERPC] spusched: Dynamic timeslicing for
SCHED_OTHER") copied SCALE_PRIO() from the task scheduler in v2.6.23.

Commit a4ec24b4 ("sched: tidy up SCHED_RR") removed it from the task
scheduler in v2.6.24.

Commit 3ee237dd ("sched/prio: Add 3 macros of MAX_NICE, MIN_NICE and
NICE_WIDTH in prio.h") introduced NICE_WIDTH much later.

With:

  MAX_USER_PRIO = USER_PRIO(MAX_PRIO)

                = MAX_PRIO - MAX_RT_PRIO

       MAX_PRIO = MAX_RT_PRIO + NICE_WIDTH

  MAX_USER_PRIO = MAX_RT_PRIO + NICE_WIDTH - MAX_RT_PRIO

  MAX_USER_PRIO = NICE_WIDTH

MAX_USER_PRIO can be replaced by NICE_WIDTH to be able to remove all the
{*_}USER_PRIO defines.

Signed-off-by: default avatarDietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20210128131040.296856-3-dietmar.eggemann@arm.com
parent ae18ad28

arch/powerpc/platforms/cell/spufs/sched.c

+1 −1
Original line number Diff line number Diff line
@@ -72,7 +72,7 @@ static struct timer_list spuloadavg_timer; 
#define DEF_SPU_TIMESLICE	(100 * HZ / (1000 * SPUSCHED_TICK))



#define SCALE_PRIO(x, prio) \

	max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_SPU_TIMESLICE)

	max(x * (MAX_PRIO - prio) / (NICE_WIDTH / 2), MIN_SPU_TIMESLICE)



/*

 * scale user-nice values [ -20 ... 0 ... 19 ] to time slice values:

include/linux/sched/prio.h

+0 −9
Original line number Diff line number Diff line
@@ -26,15 +26,6 @@ 
#define NICE_TO_PRIO(nice)	((nice) + DEFAULT_PRIO)

#define PRIO_TO_NICE(prio)	((prio) - DEFAULT_PRIO)



/*

 * 'User priority' is the nice value converted to something we

 * can work with better when scaling various scheduler parameters,

 * it's a [ 0 ... 39 ] range.

 */

#define USER_PRIO(p)		((p)-MAX_RT_PRIO)

#define TASK_USER_PRIO(p)	USER_PRIO((p)->static_prio)

#define MAX_USER_PRIO		(USER_PRIO(MAX_PRIO))



/*

 * Convert nice value [19,-20] to rlimit style value [1,40].

 */

kernel/sched/sched.h

+1 −1
Original line number Diff line number Diff line
@@ -140,7 +140,7 @@ extern void call_trace_sched_update_nr_running(struct rq *rq, int count); 
 * scale_load() and scale_load_down(w) to convert between them. The

 * following must be true:

 *

 *  scale_load(sched_prio_to_weight[USER_PRIO(NICE_TO_PRIO(0))]) == NICE_0_LOAD

 *  scale_load(sched_prio_to_weight[NICE_TO_PRIO(0)-MAX_RT_PRIO]) == NICE_0_LOAD

 *

 */

#define NICE_0_LOAD		(1L << NICE_0_LOAD_SHIFT)