Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
sched_ext: Simplify task state handling
Task states (NONE, INIT, READY, ENABLED) were defined in a separate enum with
unshifted values and then shifted when stored in scx_entity.flags. Simplify by
defining them as pre-shifted values directly in scx_ent_flags and removing the
separate scx_task_state enum. This removes the need for shifting when
reading/writing state values.
scx_get_task_state() now returns the masked flags value directly.
scx_set_task_state() accepts the pre-shifted state value. scx_dump_task()
shifts down for display to maintain readable output.
No functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
+25
-22
+16
-12
include/linux/sched/ext.h
+16
-12
include/linux/sched/ext.h
···
93
93
struct rcu_head rcu;
94
94
};
95
95
96
-
/* scx_entity.flags */
96
+
/* sched_ext_entity.flags */
97
97
enum scx_ent_flags {
98
98
SCX_TASK_QUEUED = 1 << 0, /* on ext runqueue */
99
99
SCX_TASK_IN_CUSTODY = 1 << 1, /* in custody, needs ops.dequeue() when leaving */
···
101
101
SCX_TASK_DEQD_FOR_SLEEP = 1 << 3, /* last dequeue was for SLEEP */
102
102
SCX_TASK_SUB_INIT = 1 << 4, /* task being initialized for a sub sched */
103
103
104
-
SCX_TASK_STATE_SHIFT = 8, /* bit 8 and 9 are used to carry scx_task_state */
104
+
/*
105
+
* Bits 8 and 9 are used to carry task state:
106
+
*
107
+
* NONE ops.init_task() not called yet
108
+
* INIT ops.init_task() succeeded, but task can be cancelled
109
+
* READY fully initialized, but not in sched_ext
110
+
* ENABLED fully initialized and in sched_ext
111
+
*/
112
+
SCX_TASK_STATE_SHIFT = 8, /* bits 8 and 9 are used to carry task state */
105
113
SCX_TASK_STATE_BITS = 2,
106
114
SCX_TASK_STATE_MASK = ((1 << SCX_TASK_STATE_BITS) - 1) << SCX_TASK_STATE_SHIFT,
107
115
108
-
SCX_TASK_CURSOR = 1 << 31, /* iteration cursor, not a task */
109
-
};
116
+
SCX_TASK_NONE = 0 << SCX_TASK_STATE_SHIFT,
117
+
SCX_TASK_INIT = 1 << SCX_TASK_STATE_SHIFT,
118
+
SCX_TASK_READY = 2 << SCX_TASK_STATE_SHIFT,
119
+
SCX_TASK_ENABLED = 3 << SCX_TASK_STATE_SHIFT,
110
120
111
-
/* scx_entity.flags & SCX_TASK_STATE_MASK */
112
-
enum scx_task_state {
113
-
SCX_TASK_NONE, /* ops.init_task() not called yet */
114
-
SCX_TASK_INIT, /* ops.init_task() succeeded, but task can be cancelled */
115
-
SCX_TASK_READY, /* fully initialized, but not in sched_ext */
116
-
SCX_TASK_ENABLED, /* fully initialized and in sched_ext */
117
-
118
-
SCX_TASK_NR_STATES,
121
+
/* iteration cursor, not a task */
122
+
SCX_TASK_CURSOR = 1 << 31,
119
123
};
120
124
121
125
/* scx_entity.dsq_flags */
+9
-10
kernel/sched/ext.c
+9
-10
kernel/sched/ext.c
···
3284
3284
3285
3285
#endif /* CONFIG_EXT_GROUP_SCHED */
3286
3286
3287
-
static enum scx_task_state scx_get_task_state(const struct task_struct *p)
3287
+
static u32 scx_get_task_state(const struct task_struct *p)
3288
3288
{
3289
-
return (p->scx.flags & SCX_TASK_STATE_MASK) >> SCX_TASK_STATE_SHIFT;
3289
+
return p->scx.flags & SCX_TASK_STATE_MASK;
3290
3290
}
3291
3291
3292
-
static void scx_set_task_state(struct task_struct *p, enum scx_task_state state)
3292
+
static void scx_set_task_state(struct task_struct *p, u32 state)
3293
3293
{
3294
-
enum scx_task_state prev_state = scx_get_task_state(p);
3294
+
u32 prev_state = scx_get_task_state(p);
3295
3295
bool warn = false;
3296
-
3297
-
BUILD_BUG_ON(SCX_TASK_NR_STATES > (1 << SCX_TASK_STATE_BITS));
3298
3296
3299
3297
switch (state) {
3300
3298
case SCX_TASK_NONE:
···
3311
3313
return;
3312
3314
}
3313
3315
3314
-
WARN_ONCE(warn, "sched_ext: Invalid task state transition %d -> %d for %s[%d]",
3316
+
WARN_ONCE(warn, "sched_ext: Invalid task state transition 0x%x -> 0x%x for %s[%d]",
3315
3317
prev_state, state, p->comm, p->pid);
3316
3318
3317
3319
p->scx.flags &= ~SCX_TASK_STATE_MASK;
3318
-
p->scx.flags |= state << SCX_TASK_STATE_SHIFT;
3320
+
p->scx.flags |= state;
3319
3321
}
3320
3322
3321
3323
static int __scx_init_task(struct scx_sched *sch, struct task_struct *p, bool fork)
···
5792
5794
own_marker, sch_id_buf,
5793
5795
jiffies_delta_msecs(p->scx.runnable_at, dctx->at_jiffies));
5794
5796
dump_line(s, " scx_state/flags=%u/0x%x dsq_flags=0x%x ops_state/qseq=%lu/%lu",
5795
-
scx_get_task_state(p), p->scx.flags & ~SCX_TASK_STATE_MASK,
5797
+
scx_get_task_state(p) >> SCX_TASK_STATE_SHIFT,
5798
+
p->scx.flags & ~SCX_TASK_STATE_MASK,
5796
5799
p->scx.dsq_flags, ops_state & SCX_OPSS_STATE_MASK,
5797
5800
ops_state >> SCX_OPSS_QSEQ_SHIFT);
5798
5801
dump_line(s, " sticky/holding_cpu=%d/%d dsq_id=%s",
···
6557
6558
6558
6559
static bool assert_task_ready_or_enabled(struct task_struct *p)
6559
6560
{
6560
-
enum scx_task_state state = scx_get_task_state(p);
6561
+
u32 state = scx_get_task_state(p);
6561
6562
6562
6563
switch (state) {
6563
6564
case SCX_TASK_READY: