From: Tejun Heo Date: Sat, 7 Mar 2026 15:29:50 +0000 (-1000) Subject: sched_ext: Simplify task state handling X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7203d77d6e04f83f7b78838eed099d9cac31700b;p=thirdparty%2Flinux.git 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 Reviewed-by: Andrea Righi --- diff --git a/include/linux/sched/ext.h b/include/linux/sched/ext.h index e77504faa0bcb..e822b374b17f8 100644 --- a/include/linux/sched/ext.h +++ b/include/linux/sched/ext.h @@ -93,7 +93,7 @@ struct scx_dispatch_q { struct rcu_head rcu; }; -/* scx_entity.flags */ +/* sched_ext_entity.flags */ enum scx_ent_flags { SCX_TASK_QUEUED = 1 << 0, /* on ext runqueue */ SCX_TASK_IN_CUSTODY = 1 << 1, /* in custody, needs ops.dequeue() when leaving */ @@ -101,21 +101,25 @@ enum scx_ent_flags { SCX_TASK_DEQD_FOR_SLEEP = 1 << 3, /* last dequeue was for SLEEP */ SCX_TASK_SUB_INIT = 1 << 4, /* task being initialized for a sub sched */ - SCX_TASK_STATE_SHIFT = 8, /* bit 8 and 9 are used to carry scx_task_state */ + /* + * Bits 8 and 9 are used to carry task state: + * + * NONE ops.init_task() not called yet + * INIT ops.init_task() succeeded, but task can be cancelled + * READY fully initialized, but not in sched_ext + * ENABLED fully initialized and in sched_ext + */ + SCX_TASK_STATE_SHIFT = 8, /* bits 8 and 9 are used to carry task state */ SCX_TASK_STATE_BITS = 2, SCX_TASK_STATE_MASK = ((1 << SCX_TASK_STATE_BITS) - 1) << SCX_TASK_STATE_SHIFT, - SCX_TASK_CURSOR = 1 << 31, /* iteration cursor, not a task */ -}; - -/* scx_entity.flags & SCX_TASK_STATE_MASK */ -enum scx_task_state { - SCX_TASK_NONE, /* ops.init_task() not called yet */ - SCX_TASK_INIT, /* ops.init_task() succeeded, but task can be cancelled */ - SCX_TASK_READY, /* fully initialized, but not in sched_ext */ - SCX_TASK_ENABLED, /* fully initialized and in sched_ext */ + SCX_TASK_NONE = 0 << SCX_TASK_STATE_SHIFT, + SCX_TASK_INIT = 1 << SCX_TASK_STATE_SHIFT, + SCX_TASK_READY = 2 << SCX_TASK_STATE_SHIFT, + SCX_TASK_ENABLED = 3 << SCX_TASK_STATE_SHIFT, - SCX_TASK_NR_STATES, + /* iteration cursor, not a task */ + SCX_TASK_CURSOR = 1 << 31, }; /* scx_entity.dsq_flags */ diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index ee756f1a70e1d..f55e1603fc8ce 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -3284,18 +3284,16 @@ static struct cgroup *tg_cgrp(struct task_group *tg) #endif /* CONFIG_EXT_GROUP_SCHED */ -static enum scx_task_state scx_get_task_state(const struct task_struct *p) +static u32 scx_get_task_state(const struct task_struct *p) { - return (p->scx.flags & SCX_TASK_STATE_MASK) >> SCX_TASK_STATE_SHIFT; + return p->scx.flags & SCX_TASK_STATE_MASK; } -static void scx_set_task_state(struct task_struct *p, enum scx_task_state state) +static void scx_set_task_state(struct task_struct *p, u32 state) { - enum scx_task_state prev_state = scx_get_task_state(p); + u32 prev_state = scx_get_task_state(p); bool warn = false; - BUILD_BUG_ON(SCX_TASK_NR_STATES > (1 << SCX_TASK_STATE_BITS)); - switch (state) { case SCX_TASK_NONE: break; @@ -3313,11 +3311,11 @@ static void scx_set_task_state(struct task_struct *p, enum scx_task_state state) return; } - WARN_ONCE(warn, "sched_ext: Invalid task state transition %d -> %d for %s[%d]", + WARN_ONCE(warn, "sched_ext: Invalid task state transition 0x%x -> 0x%x for %s[%d]", prev_state, state, p->comm, p->pid); p->scx.flags &= ~SCX_TASK_STATE_MASK; - p->scx.flags |= state << SCX_TASK_STATE_SHIFT; + p->scx.flags |= state; } static int __scx_init_task(struct scx_sched *sch, struct task_struct *p, bool fork) @@ -5794,7 +5792,8 @@ static void scx_dump_task(struct scx_sched *sch, own_marker, sch_id_buf, jiffies_delta_msecs(p->scx.runnable_at, dctx->at_jiffies)); dump_line(s, " scx_state/flags=%u/0x%x dsq_flags=0x%x ops_state/qseq=%lu/%lu", - scx_get_task_state(p), p->scx.flags & ~SCX_TASK_STATE_MASK, + scx_get_task_state(p) >> SCX_TASK_STATE_SHIFT, + p->scx.flags & ~SCX_TASK_STATE_MASK, p->scx.dsq_flags, ops_state & SCX_OPSS_STATE_MASK, ops_state >> SCX_OPSS_QSEQ_SHIFT); dump_line(s, " sticky/holding_cpu=%d/%d dsq_id=%s", @@ -6558,7 +6557,7 @@ static struct scx_sched *find_parent_sched(struct cgroup *cgrp) static bool assert_task_ready_or_enabled(struct task_struct *p) { - enum scx_task_state state = scx_get_task_state(p); + u32 state = scx_get_task_state(p); switch (state) { case SCX_TASK_READY: