[tip: sched/core] sched: Remove USER_PRIO, TASK_USER_PRIO and MAX_USER_PRIO

From: tip-bot2 for Dietmar Eggemann
Date: Wed Feb 17 2021 - 08:28:34 EST


The following commit has been merged into the sched/core branch of tip:

Commit-ID: 9d061ba6bc170045857f3efe0bba5def30188d4d
Gitweb: https://git.kernel.org/tip/9d061ba6bc170045857f3efe0bba5def30188d4d
Author: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
AuthorDate: Thu, 28 Jan 2021 14:10:39 +01:00
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 17 Feb 2021 14:08:17 +01:00

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 fe443ef2ac42 ("[POWERPC] spusched: Dynamic timeslicing for
SCHED_OTHER") copied SCALE_PRIO() from the task scheduler in v2.6.23.

Commit a4ec24b48dde ("sched: tidy up SCHED_RR") removed it from the task
scheduler in v2.6.24.

Commit 3ee237dddcd8 ("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: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20210128131040.296856-3-dietmar.eggemann@xxxxxxx
---
arch/powerpc/platforms/cell/spufs/sched.c | 2 +-
include/linux/sched/prio.h | 9 ---------
kernel/sched/sched.h | 2 +-
3 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index f18d506..aeb7f39 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -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:
diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
index d111f2f..ab83d85 100644
--- a/include/linux/sched/prio.h
+++ b/include/linux/sched/prio.h
@@ -27,15 +27,6 @@
#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].
*/
static inline long nice_to_rlimit(long nice)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index f519aba..2185b3b 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -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)