(1) Removing MAX_USER_RT_PRIO was already discussed here in April 2020:
https://lkml.kernel.org/r/[email protected]
(2) USER_PRIO() and related macros are not used anymore except in one
case for powerpc where MAX_USER_PRIO can be replaced by NICE_WIDTH.
Set_load_weight(), task_prio(), cpu_weight_nice_write_s64(),
__update_max_tr() don't use USER_PRIO() but priority - MAX_RT_PRIO.
(3) The function header of task_prio() needs an update. It looks
ancient since it mentions a prio space [-16 ... 15] for mormal
tasks. I can't figure out why this range is mentioned here? Maybe
the influence of the 'sleep-bonus interactivity' feature which was
removed by commit f3479f10c5d6 ("sched: remove the sleep-bonus
interactivity code")?
Dietmar Eggemann (3):
sched: Remove MAX_USER_RT_PRIO
sched: Remove USER_PRIO, TASK_USER_PRIO and MAX_USER_PRIO
sched/core: Update task_prio() function header
arch/powerpc/platforms/cell/spufs/sched.c | 2 +-
include/linux/sched/prio.h | 18 +-----------------
kernel/sched/core.c | 15 +++++++++------
kernel/sched/sched.h | 2 +-
4 files changed, 12 insertions(+), 25 deletions(-)
--
2.25.1
The description of the RT offset and the values for 'normal' tasks needs
update. Moreover there are DL tasks now.
task_prio() has to stay like it is to guarantee compatibility with the
/proc/<pid>/stat priority field:
# cat /proc/<pid>/stat | awk '{ print $18; }'
Signed-off-by: Dietmar Eggemann <[email protected]>
---
kernel/sched/core.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 625ec1e12064..be3a956c2d23 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5602,8 +5602,12 @@ SYSCALL_DEFINE1(nice, int, increment)
* @p: the task in question.
*
* Return: The priority value as seen by users in /proc.
- * RT tasks are offset by -200. Normal tasks are centered
- * around 0, value goes from -16 to +15.
+ *
+ * sched policy return value kernel prio user prio/nice
+ *
+ * normal, batch, idle [0 ... 39] [100 ... 139] 0/[-20 ... 19]
+ * fifo, rr [-2 ... -100] [98 ... 0] [1 ... 99]
+ * deadline -101 -1 0
*/
int task_prio(const struct task_struct *p)
{
--
2.25.1
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 <[email protected]>
---
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 f18d5067cd0f..aeb7f3922106 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 d111f2fd77ea..ab83d85e1183 100644
--- a/include/linux/sched/prio.h
+++ b/include/linux/sched/prio.h
@@ -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].
*/
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 045b01064c1e..6edc67df3554 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)
--
2.25.1
Commit d46523ea32a7 ("[PATCH] fix MAX_USER_RT_PRIO and MAX_RT_PRIO")
was introduced due to a a small time period in which the realtime patch
set was using different values for MAX_USER_RT_PRIO and MAX_RT_PRIO.
This is no longer true, i.e. now MAX_RT_PRIO == MAX_USER_RT_PRIO.
Get rid of MAX_USER_RT_PRIO and make everything use MAX_RT_PRIO
instead.
Signed-off-by: Dietmar Eggemann <[email protected]>
---
include/linux/sched/prio.h | 9 +--------
kernel/sched/core.c | 7 +++----
2 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
index 7d64feafc408..d111f2fd77ea 100644
--- a/include/linux/sched/prio.h
+++ b/include/linux/sched/prio.h
@@ -11,16 +11,9 @@
* priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
* tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
* values are inverted: lower p->prio value means higher priority.
- *
- * The MAX_USER_RT_PRIO value allows the actual maximum
- * RT priority to be separate from the value exported to
- * user-space. This allows kernel threads to set their
- * priority to a value higher than any user task. Note:
- * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
*/
-#define MAX_USER_RT_PRIO 100
-#define MAX_RT_PRIO MAX_USER_RT_PRIO
+#define MAX_RT_PRIO 100
#define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
#define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 06b449942adf..625ec1e12064 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5897,11 +5897,10 @@ static int __sched_setscheduler(struct task_struct *p,
/*
* Valid priorities for SCHED_FIFO and SCHED_RR are
- * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
+ * 1..MAX_RT_PRIO-1, valid priority for SCHED_NORMAL,
* SCHED_BATCH and SCHED_IDLE is 0.
*/
- if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) ||
- (!p->mm && attr->sched_priority > MAX_RT_PRIO-1))
+ if (attr->sched_priority > MAX_RT_PRIO-1)
return -EINVAL;
if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
(rt_policy(policy) != (attr->sched_priority != 0)))
@@ -6969,7 +6968,7 @@ SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
- ret = MAX_USER_RT_PRIO-1;
+ ret = MAX_RT_PRIO-1;
break;
case SCHED_DEADLINE:
case SCHED_NORMAL:
--
2.25.1
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 075a28439d0c8eb6d3c799e1eed24bb9bc7750cd
Gitweb: https://git.kernel.org/tip/075a28439d0c8eb6d3c799e1eed24bb9bc7750cd
Author: Dietmar Eggemann <[email protected]>
AuthorDate: Thu, 28 Jan 2021 14:10:40 +01:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Mon, 01 Feb 2021 15:31:39 +01:00
sched/core: Update task_prio() function header
The description of the RT offset and the values for 'normal' tasks needs
update. Moreover there are DL tasks now.
task_prio() has to stay like it is to guarantee compatibility with the
/proc/<pid>/stat priority field:
# cat /proc/<pid>/stat | awk '{ print $18; }'
Signed-off-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
kernel/sched/core.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 625ec1e..be3a956 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5602,8 +5602,12 @@ SYSCALL_DEFINE1(nice, int, increment)
* @p: the task in question.
*
* Return: The priority value as seen by users in /proc.
- * RT tasks are offset by -200. Normal tasks are centered
- * around 0, value goes from -16 to +15.
+ *
+ * sched policy return value kernel prio user prio/nice
+ *
+ * normal, batch, idle [0 ... 39] [100 ... 139] 0/[-20 ... 19]
+ * fifo, rr [-2 ... -100] [98 ... 0] [1 ... 99]
+ * deadline -101 -1 0
*/
int task_prio(const struct task_struct *p)
{
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 4d38ea6a6d93115113fb4c023d5bb15e8ce1589c
Gitweb: https://git.kernel.org/tip/4d38ea6a6d93115113fb4c023d5bb15e8ce1589c
Author: Dietmar Eggemann <[email protected]>
AuthorDate: Thu, 28 Jan 2021 14:10:38 +01:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Mon, 01 Feb 2021 15:31:39 +01:00
sched: Remove MAX_USER_RT_PRIO
Commit d46523ea32a7 ("[PATCH] fix MAX_USER_RT_PRIO and MAX_RT_PRIO")
was introduced due to a a small time period in which the realtime patch
set was using different values for MAX_USER_RT_PRIO and MAX_RT_PRIO.
This is no longer true, i.e. now MAX_RT_PRIO == MAX_USER_RT_PRIO.
Get rid of MAX_USER_RT_PRIO and make everything use MAX_RT_PRIO
instead.
Signed-off-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
include/linux/sched/prio.h | 9 +--------
kernel/sched/core.c | 7 +++----
2 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
index 7d64fea..d111f2f 100644
--- a/include/linux/sched/prio.h
+++ b/include/linux/sched/prio.h
@@ -11,16 +11,9 @@
* priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
* tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
* values are inverted: lower p->prio value means higher priority.
- *
- * The MAX_USER_RT_PRIO value allows the actual maximum
- * RT priority to be separate from the value exported to
- * user-space. This allows kernel threads to set their
- * priority to a value higher than any user task. Note:
- * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
*/
-#define MAX_USER_RT_PRIO 100
-#define MAX_RT_PRIO MAX_USER_RT_PRIO
+#define MAX_RT_PRIO 100
#define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
#define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 06b4499..625ec1e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5897,11 +5897,10 @@ recheck:
/*
* Valid priorities for SCHED_FIFO and SCHED_RR are
- * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
+ * 1..MAX_RT_PRIO-1, valid priority for SCHED_NORMAL,
* SCHED_BATCH and SCHED_IDLE is 0.
*/
- if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) ||
- (!p->mm && attr->sched_priority > MAX_RT_PRIO-1))
+ if (attr->sched_priority > MAX_RT_PRIO-1)
return -EINVAL;
if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
(rt_policy(policy) != (attr->sched_priority != 0)))
@@ -6969,7 +6968,7 @@ SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
- ret = MAX_USER_RT_PRIO-1;
+ ret = MAX_RT_PRIO-1;
break;
case SCHED_DEADLINE:
case SCHED_NORMAL:
The following commit has been merged into the sched/core branch of tip:
Commit-ID: c18b4a67cc459fb8389f6a89ce28e404aafe562c
Gitweb: https://git.kernel.org/tip/c18b4a67cc459fb8389f6a89ce28e404aafe562c
Author: Dietmar Eggemann <[email protected]>
AuthorDate: Thu, 28 Jan 2021 14:10:39 +01:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Mon, 01 Feb 2021 15:31:39 +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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
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 045b010..6edc67d 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)
The following commit has been merged into the sched/core branch of tip:
Commit-ID: ae18ad281e825993d190073d0ae2ea35dee27ee1
Gitweb: https://git.kernel.org/tip/ae18ad281e825993d190073d0ae2ea35dee27ee1
Author: Dietmar Eggemann <[email protected]>
AuthorDate: Thu, 28 Jan 2021 14:10:38 +01:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Wed, 17 Feb 2021 14:08:11 +01:00
sched: Remove MAX_USER_RT_PRIO
Commit d46523ea32a7 ("[PATCH] fix MAX_USER_RT_PRIO and MAX_RT_PRIO")
was introduced due to a a small time period in which the realtime patch
set was using different values for MAX_USER_RT_PRIO and MAX_RT_PRIO.
This is no longer true, i.e. now MAX_RT_PRIO == MAX_USER_RT_PRIO.
Get rid of MAX_USER_RT_PRIO and make everything use MAX_RT_PRIO
instead.
Signed-off-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
include/linux/sched/prio.h | 9 +--------
kernel/sched/core.c | 7 +++----
2 files changed, 4 insertions(+), 12 deletions(-)
diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
index 7d64fea..d111f2f 100644
--- a/include/linux/sched/prio.h
+++ b/include/linux/sched/prio.h
@@ -11,16 +11,9 @@
* priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH
* tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. Priority
* values are inverted: lower p->prio value means higher priority.
- *
- * The MAX_USER_RT_PRIO value allows the actual maximum
- * RT priority to be separate from the value exported to
- * user-space. This allows kernel threads to set their
- * priority to a value higher than any user task. Note:
- * MAX_RT_PRIO must not be smaller than MAX_USER_RT_PRIO.
*/
-#define MAX_USER_RT_PRIO 100
-#define MAX_RT_PRIO MAX_USER_RT_PRIO
+#define MAX_RT_PRIO 100
#define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
#define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 6c789dc..f0b0b67 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5911,11 +5911,10 @@ recheck:
/*
* Valid priorities for SCHED_FIFO and SCHED_RR are
- * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
+ * 1..MAX_RT_PRIO-1, valid priority for SCHED_NORMAL,
* SCHED_BATCH and SCHED_IDLE is 0.
*/
- if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) ||
- (!p->mm && attr->sched_priority > MAX_RT_PRIO-1))
+ if (attr->sched_priority > MAX_RT_PRIO-1)
return -EINVAL;
if ((dl_policy(policy) && !__checkparam_dl(attr)) ||
(rt_policy(policy) != (attr->sched_priority != 0)))
@@ -6983,7 +6982,7 @@ SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
- ret = MAX_USER_RT_PRIO-1;
+ ret = MAX_RT_PRIO-1;
break;
case SCHED_DEADLINE:
case SCHED_NORMAL:
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 <[email protected]>
AuthorDate: Thu, 28 Jan 2021 14:10:39 +01:00
Committer: Ingo Molnar <[email protected]>
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 <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
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)
The following commit has been merged into the sched/core branch of tip:
Commit-ID: c541bb7835a306cdbbe8abbdf4e4df507e0ca27a
Gitweb: https://git.kernel.org/tip/c541bb7835a306cdbbe8abbdf4e4df507e0ca27a
Author: Dietmar Eggemann <[email protected]>
AuthorDate: Thu, 28 Jan 2021 14:10:40 +01:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Wed, 17 Feb 2021 14:08:30 +01:00
sched/core: Update task_prio() function header
The description of the RT offset and the values for 'normal' tasks needs
update. Moreover there are DL tasks now.
task_prio() has to stay like it is to guarantee compatibility with the
/proc/<pid>/stat priority field:
# cat /proc/<pid>/stat | awk '{ print $18; }'
Signed-off-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
kernel/sched/core.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f0b0b67..4afbdd2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5616,8 +5616,12 @@ SYSCALL_DEFINE1(nice, int, increment)
* @p: the task in question.
*
* Return: The priority value as seen by users in /proc.
- * RT tasks are offset by -200. Normal tasks are centered
- * around 0, value goes from -16 to +15.
+ *
+ * sched policy return value kernel prio user prio/nice
+ *
+ * normal, batch, idle [0 ... 39] [100 ... 139] 0/[-20 ... 19]
+ * fifo, rr [-2 ... -100] [98 ... 0] [1 ... 99]
+ * deadline -101 -1 0
*/
int task_prio(const struct task_struct *p)
{