* [PATCH v4 1/1] sched/uclamp: add SCHED_FLAG_UTIL_CLAMP_RESET flag to reset uclamp
@ 2020-11-01 8:44 Yun Hsiang
2020-11-02 20:51 ` kernel test robot
0 siblings, 1 reply; 2+ messages in thread
From: Yun Hsiang @ 2020-11-01 8:44 UTC (permalink / raw)
To: dietmar.eggemann, peterz
Cc: linux-kernel, qais.yousef, patrick.bellasi, Yun Hsiang
If the user wants to stop controlling uclamp and let the task inherit
the value from the group, we need a method to reset.
Add SCHED_FLAG_UTIL_CLAMP_RESET flag to allow the user to reset uclamp via
sched_setattr syscall.
The policy is
_CLAMP_RESET => reset both min and max
_CLAMP_RESET | _CLAMP_MIN => reset min value
_CLAMP_RESET | _CLAMP_MAX => reset max value
_CLAMP_RESET | _CLAMP_MIN | _CLAMP_MAX => reset both min and max
Signed-off-by: Yun Hsiang <hsiang023167@gmail.com>
---
include/uapi/linux/sched.h | 7 +++--
kernel/sched/core.c | 59 ++++++++++++++++++++++++++++----------
2 files changed, 49 insertions(+), 17 deletions(-)
diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
index 3bac0a8ceab2..6c823ddb1a1e 100644
--- a/include/uapi/linux/sched.h
+++ b/include/uapi/linux/sched.h
@@ -132,17 +132,20 @@ struct clone_args {
#define SCHED_FLAG_KEEP_PARAMS 0x10
#define SCHED_FLAG_UTIL_CLAMP_MIN 0x20
#define SCHED_FLAG_UTIL_CLAMP_MAX 0x40
+#define SCHED_FLAG_UTIL_CLAMP_RESET 0x80
#define SCHED_FLAG_KEEP_ALL (SCHED_FLAG_KEEP_POLICY | \
SCHED_FLAG_KEEP_PARAMS)
#define SCHED_FLAG_UTIL_CLAMP (SCHED_FLAG_UTIL_CLAMP_MIN | \
- SCHED_FLAG_UTIL_CLAMP_MAX)
+ SCHED_FLAG_UTIL_CLAMP_MAX | \
+ SCHED_FLAG_UTIL_CLAMP_RESET)
#define SCHED_FLAG_ALL (SCHED_FLAG_RESET_ON_FORK | \
SCHED_FLAG_RECLAIM | \
SCHED_FLAG_DL_OVERRUN | \
SCHED_FLAG_KEEP_ALL | \
- SCHED_FLAG_UTIL_CLAMP)
+ SCHED_FLAG_UTIL_CLAMP | \
+ SCHED_FLAG_UTIL_CLAMP_RESET)
#endif /* _UAPI_LINUX_SCHED_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 8160ab5263f8..2b644f4bf2eb 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1004,7 +1004,7 @@ unsigned int uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id,
return uclamp_idle_value(rq, clamp_id, clamp_value);
}
-static void __uclamp_update_util_min_rt_default(struct task_struct *p)
+static inline void __uclamp_update_util_min_rt_default(struct task_struct *p)
{
unsigned int default_util_min;
struct uclamp_se *uc_se;
@@ -1413,8 +1413,14 @@ int sysctl_sched_uclamp_handler(struct ctl_table *table, int write,
static int uclamp_validate(struct task_struct *p,
const struct sched_attr *attr)
{
- unsigned int lower_bound = p->uclamp_req[UCLAMP_MIN].value;
- unsigned int upper_bound = p->uclamp_req[UCLAMP_MAX].value;
+ unsigned int lower_bound, upper_bound;
+
+ /* Do not check uclamp attributes values in reset case. */
+ if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_RESET)
+ return 0;
+
+ lower_bound = p->uclamp_req[UCLAMP_MIN].value;
+ upper_bound = p->uclamp_req[UCLAMP_MAX].value;
if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN)
lower_bound = attr->sched_util_min;
@@ -1438,20 +1444,43 @@ static int uclamp_validate(struct task_struct *p,
return 0;
}
+static int uclamp_reset(enum uclamp_id clamp_id, unsigned long flags)
+{
+ /* No _UCLAMP_RESET flag set: do not reset */
+ if (!(flags & SCHED_FLAG_UTIL_CLAMP_RESET))
+ return false;
+
+ /* Only _UCLAMP_RESET flag set: reset both clamps */
+ if (!(flags & (SCHED_FLAG_UTIL_CLAMP_MIN | SCHED_FLAG_UTIL_CLAMP_MAX)))
+ return true;
+
+ /* Both _UCLAMP_RESET and _UCLAMP_MIN flags are set: reset only min */
+ if ((flags & SCHED_FLAG_UTIL_CLAMP_MIN) && clamp_id == UCLAMP_MIN)
+ return true;
+
+ /* Both _UCLAMP_RESET and _UCLAMP_MAX flags are set: reset only max */
+ if ((flags & SCHED_FLAG_UTIL_CLAMP_MAX) && clamp_id == UCLAMP_MAX)
+ return true;
+
+ return false;
+}
+
static void __setscheduler_uclamp(struct task_struct *p,
const struct sched_attr *attr)
{
+ unsigned int clamp_value;
enum uclamp_id clamp_id;
/*
- * On scheduling class change, reset to default clamps for tasks
- * without a task-specific value.
+ * Reset to default clamps on forced _UCLAMP_RESET (always) and
+ * for tasks without a task-specific value (on scheduling class change).
*/
for_each_clamp_id(clamp_id) {
struct uclamp_se *uc_se = &p->uclamp_req[clamp_id];
/* Keep using defined clamps across class changes */
- if (uc_se->user_defined)
+ if (!uclamp_reset(clamp_id, attr->sched_flags) &&
+ uc_se->user_defined)
continue;
/*
@@ -1459,24 +1488,24 @@ static void __setscheduler_uclamp(struct task_struct *p,
* at runtime.
*/
if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN))
- __uclamp_update_util_min_rt_default(p);
+ clamp_value = sysctl_sched_uclamp_util_min_rt_default;
else
- uclamp_se_set(uc_se, uclamp_none(clamp_id), false);
+ clamp_value = uclamp_none(clamp_id);
+ uclamp_se_set(uc_se, uclamp_none(clamp_id), false);
}
- if (likely(!(attr->sched_flags & SCHED_FLAG_UTIL_CLAMP)))
+ if (likely(!(attr->sched_flags && SCHED_FLAG_UTIL_CLAMP)) ||
+ attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_RESET)
return;
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN) {
+ if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN)
uclamp_se_set(&p->uclamp_req[UCLAMP_MIN],
- attr->sched_util_min, true);
- }
+ attr->sched_util_min, true);
- if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX) {
+ if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX)
uclamp_se_set(&p->uclamp_req[UCLAMP_MAX],
- attr->sched_util_max, true);
- }
+ attr->sched_util_max, true);
}
static void uclamp_fork(struct task_struct *p)
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v4 1/1] sched/uclamp: add SCHED_FLAG_UTIL_CLAMP_RESET flag to reset uclamp
2020-11-01 8:44 [PATCH v4 1/1] sched/uclamp: add SCHED_FLAG_UTIL_CLAMP_RESET flag to reset uclamp Yun Hsiang
@ 2020-11-02 20:51 ` kernel test robot
0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2020-11-02 20:51 UTC (permalink / raw)
To: Yun Hsiang, dietmar.eggemann, peterz
Cc: kbuild-all, linux-kernel, qais.yousef, patrick.bellasi, Yun Hsiang
[-- Attachment #1: Type: text/plain, Size: 3515 bytes --]
Hi Yun,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on tip/sched/core]
[also build test WARNING on v5.10-rc2 next-20201102]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Yun-Hsiang/sched-uclamp-add-SCHED_FLAG_UTIL_CLAMP_RESET-flag-to-reset-uclamp/20201101-164635
base: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git d8fcb81f1acf651a0e50eacecca43d0524984f87
config: x86_64-allyesconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
# https://github.com/0day-ci/linux/commit/b705c245791a37b85013c6604ee1301022312dc5
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Yun-Hsiang/sched-uclamp-add-SCHED_FLAG_UTIL_CLAMP_RESET-flag-to-reset-uclamp/20201101-164635
git checkout b705c245791a37b85013c6604ee1301022312dc5
# save the attached .config to linux build tree
make W=1 ARCH=x86_64
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
kernel/sched/core.c: In function '__setscheduler_uclamp':
>> kernel/sched/core.c:1471:15: warning: variable 'clamp_value' set but not used [-Wunused-but-set-variable]
1471 | unsigned int clamp_value;
| ^~~~~~~~~~~
kernel/sched/core.c: At top level:
kernel/sched/core.c:2405:6: warning: no previous prototype for 'sched_set_stop_task' [-Wmissing-prototypes]
2405 | void sched_set_stop_task(int cpu, struct task_struct *stop)
| ^~~~~~~~~~~~~~~~~~~
vim +/clamp_value +1471 kernel/sched/core.c
1467
1468 static void __setscheduler_uclamp(struct task_struct *p,
1469 const struct sched_attr *attr)
1470 {
> 1471 unsigned int clamp_value;
1472 enum uclamp_id clamp_id;
1473
1474 /*
1475 * Reset to default clamps on forced _UCLAMP_RESET (always) and
1476 * for tasks without a task-specific value (on scheduling class change).
1477 */
1478 for_each_clamp_id(clamp_id) {
1479 struct uclamp_se *uc_se = &p->uclamp_req[clamp_id];
1480
1481 /* Keep using defined clamps across class changes */
1482 if (!uclamp_reset(clamp_id, attr->sched_flags) &&
1483 uc_se->user_defined)
1484 continue;
1485
1486 /*
1487 * RT by default have a 100% boost value that could be modified
1488 * at runtime.
1489 */
1490 if (unlikely(rt_task(p) && clamp_id == UCLAMP_MIN))
1491 clamp_value = sysctl_sched_uclamp_util_min_rt_default;
1492 else
1493 clamp_value = uclamp_none(clamp_id);
1494
1495 uclamp_se_set(uc_se, uclamp_none(clamp_id), false);
1496 }
1497
1498 if (likely(!(attr->sched_flags && SCHED_FLAG_UTIL_CLAMP)) ||
1499 attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_RESET)
1500 return;
1501
1502 if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MIN)
1503 uclamp_se_set(&p->uclamp_req[UCLAMP_MIN],
1504 attr->sched_util_min, true);
1505
1506 if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP_MAX)
1507 uclamp_se_set(&p->uclamp_req[UCLAMP_MAX],
1508 attr->sched_util_max, true);
1509 }
1510
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 77103 bytes --]
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