Messages in this thread Patch in this message | | | From | Parth Shah <> | Subject | [RFC v4 1/8] sched/core: Add manual jitter classification using sched_setattr syscall | Date | Thu, 25 Jul 2019 12:38:50 +0530 |
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Jitter tasks are short/bursty tasks, typically performing some housekeeping work and are less important in the overall scheme of things.
So provide a way to mark the task as jitter with the use of additional flag to the existing task attribute. Also provide an interface from the userspace which uses sched_setattr syscall to mark tasks as jitter.
Signed-off-by: Parth Shah <parth@linux.ibm.com> --- include/linux/sched.h | 1 + include/uapi/linux/sched.h | 4 +++- kernel/sched/core.c | 9 +++++++++ 3 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 1113dd4706ae..e03b85166e34 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1463,6 +1463,7 @@ extern struct pid *cad_pid; #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */ #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */ #define PF_MEMALLOC_NOCMA 0x10000000 /* All allocation request will have _GFP_MOVABLE cleared */ +#define PF_CAN_BE_PACKED 0x20000000 /* Provide hints to the scheduler to pack such tasks */ #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */ #define PF_SUSPEND_TASK 0x80000000 /* This thread called freeze_processes() and should not be frozen */ diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index 617bb59aa8ba..fccb1c57d037 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -55,6 +55,7 @@ #define SCHED_FLAG_KEEP_PARAMS 0x10 #define SCHED_FLAG_UTIL_CLAMP_MIN 0x20 #define SCHED_FLAG_UTIL_CLAMP_MAX 0x40 +#define SCHED_FLAG_TASK_PACKING 0x80 #define SCHED_FLAG_KEEP_ALL (SCHED_FLAG_KEEP_POLICY | \ SCHED_FLAG_KEEP_PARAMS) @@ -66,6 +67,7 @@ SCHED_FLAG_RECLAIM | \ SCHED_FLAG_DL_OVERRUN | \ SCHED_FLAG_KEEP_ALL | \ - SCHED_FLAG_UTIL_CLAMP) + SCHED_FLAG_UTIL_CLAMP | \ + SCHED_FLAG_TASK_PACKING) #endif /* _UAPI_LINUX_SCHED_H */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fa43ce3962e7..e7cda4aa8696 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4498,6 +4498,8 @@ static void __setscheduler_params(struct task_struct *p, p->rt_priority = attr->sched_priority; p->normal_prio = normal_prio(p); set_load_weight(p, true); + if (attr->sched_flags & SCHED_FLAG_TASK_PACKING) + p->flags |= PF_CAN_BE_PACKED; } /* Actually do priority change: must hold pi & rq lock. */ @@ -4557,6 +4559,8 @@ static int __sched_setscheduler(struct task_struct *p, struct rq_flags rf; int reset_on_fork; int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK; + unsigned long long task_packing_flag = + attr->sched_flags & SCHED_FLAG_TASK_PACKING; struct rq *rq; /* The pi code expects interrupts enabled */ @@ -4686,6 +4690,8 @@ static int __sched_setscheduler(struct task_struct *p, goto change; if (attr->sched_flags & SCHED_FLAG_UTIL_CLAMP) goto change; + if (task_packing_flag) + goto change; p->sched_reset_on_fork = reset_on_fork; task_rq_unlock(rq, p, &rf); @@ -5181,6 +5187,9 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, attr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value; #endif + if (p->flags & PF_CAN_BE_PACKED) + attr.sched_flags |= SCHED_FLAG_TASK_PACKING; + rcu_read_unlock(); retval = sched_read_attr(uattr, &attr, size); -- 2.17.1
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