From: Tejun Heo <tj@kernel.org>
To: David Vernet <void@manifault.com>,
Andrea Righi <arighi@nvidia.com>,
Changwoo Min <changwoo@igalia.com>
Cc: Emil Tsalapatis <emil@etsalapatis.com>,
sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org,
Tejun Heo <tj@kernel.org>
Subject: [PATCH 2/4] tools/sched_ext: Order single-cid cmask helpers as (cid, mask)
Date: Wed, 3 Jun 2026 16:00:30 -1000 [thread overview]
Message-ID: <20260604020032.3536466-3-tj@kernel.org> (raw)
In-Reply-To: <20260604020032.3536466-1-tj@kernel.org>
The BPF arena single-cid cmask helpers take the cmask first and the cid
second. Reorder them to (cid, mask) to match the kernel-side helpers and
the test_bit(nr, addr), cpumask_test_cpu(cpu, mask) convention. Range and
iteration helpers keep (mask, start).
Signed-off-by: Tejun Heo <tj@kernel.org>
---
tools/sched_ext/include/scx/cid.bpf.h | 60 +++++++++++++--------------
tools/sched_ext/scx_qmap.bpf.c | 12 +++---
2 files changed, 36 insertions(+), 36 deletions(-)
diff --git a/tools/sched_ext/include/scx/cid.bpf.h b/tools/sched_ext/include/scx/cid.bpf.h
index 70f2a3829af4..9d89bb57e201 100644
--- a/tools/sched_ext/include/scx/cid.bpf.h
+++ b/tools/sched_ext/include/scx/cid.bpf.h
@@ -40,12 +40,12 @@
*/
#define CMASK_NR_WORDS(nr_cids) ((u32)(((u64)(nr_cids) + 63) / 64 + 1))
-static __always_inline bool __cmask_contains(const struct scx_cmask __arena *m, u32 cid)
+static __always_inline bool __cmask_contains(u32 cid, const struct scx_cmask __arena *m)
{
return cid >= m->base && cid < m->base + m->nr_cids;
}
-static __always_inline u64 __arena *__cmask_word(const struct scx_cmask __arena *m, u32 cid)
+static __always_inline u64 __arena *__cmask_word(u32 cid, const struct scx_cmask __arena *m)
{
return (u64 __arena *)&m->bits[cid / 64 - m->base / 64];
}
@@ -122,11 +122,11 @@ static __always_inline void cmask_reframe(struct scx_cmask __arena *m, u32 base,
m->nr_cids = nr_cids;
}
-static __always_inline bool cmask_test(const struct scx_cmask __arena *m, u32 cid)
+static __always_inline bool cmask_test(u32 cid, const struct scx_cmask __arena *m)
{
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return false;
- return *__cmask_word(m, cid) & BIT_U64(cid & 63);
+ return *__cmask_word(cid, m) & BIT_U64(cid & 63);
}
/*
@@ -140,15 +140,15 @@ static __always_inline bool cmask_test(const struct scx_cmask __arena *m, u32 ci
*/
#define CMASK_CAS_TRIES (1U << 23)
-static __always_inline void cmask_set(struct scx_cmask __arena *m, u32 cid)
+static __always_inline void cmask_set(u32 cid, struct scx_cmask __arena *m)
{
u64 __arena *w;
u64 bit, old, new;
u32 i;
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return;
- w = __cmask_word(m, cid);
+ w = __cmask_word(cid, m);
bit = BIT_U64(cid & 63);
bpf_for(i, 0, CMASK_CAS_TRIES) {
old = *w;
@@ -161,15 +161,15 @@ static __always_inline void cmask_set(struct scx_cmask __arena *m, u32 cid)
scx_bpf_error("cmask_set CAS exhausted at cid %u", cid);
}
-static __always_inline void cmask_clear(struct scx_cmask __arena *m, u32 cid)
+static __always_inline void cmask_clear(u32 cid, struct scx_cmask __arena *m)
{
u64 __arena *w;
u64 bit, old, new;
u32 i;
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return;
- w = __cmask_word(m, cid);
+ w = __cmask_word(cid, m);
bit = BIT_U64(cid & 63);
bpf_for(i, 0, CMASK_CAS_TRIES) {
old = *w;
@@ -182,15 +182,15 @@ static __always_inline void cmask_clear(struct scx_cmask __arena *m, u32 cid)
scx_bpf_error("cmask_clear CAS exhausted at cid %u", cid);
}
-static __always_inline bool cmask_test_and_set(struct scx_cmask __arena *m, u32 cid)
+static __always_inline bool cmask_test_and_set(u32 cid, struct scx_cmask __arena *m)
{
u64 __arena *w;
u64 bit, old, new;
u32 i;
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return false;
- w = __cmask_word(m, cid);
+ w = __cmask_word(cid, m);
bit = BIT_U64(cid & 63);
bpf_for(i, 0, CMASK_CAS_TRIES) {
old = *w;
@@ -204,15 +204,15 @@ static __always_inline bool cmask_test_and_set(struct scx_cmask __arena *m, u32
return false;
}
-static __always_inline bool cmask_test_and_clear(struct scx_cmask __arena *m, u32 cid)
+static __always_inline bool cmask_test_and_clear(u32 cid, struct scx_cmask __arena *m)
{
u64 __arena *w;
u64 bit, old, new;
u32 i;
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return false;
- w = __cmask_word(m, cid);
+ w = __cmask_word(cid, m);
bit = BIT_U64(cid & 63);
bpf_for(i, 0, CMASK_CAS_TRIES) {
old = *w;
@@ -226,43 +226,43 @@ static __always_inline bool cmask_test_and_clear(struct scx_cmask __arena *m, u3
return false;
}
-static __always_inline void __cmask_set(struct scx_cmask __arena *m, u32 cid)
+static __always_inline void __cmask_set(u32 cid, struct scx_cmask __arena *m)
{
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return;
- *__cmask_word(m, cid) |= BIT_U64(cid & 63);
+ *__cmask_word(cid, m) |= BIT_U64(cid & 63);
}
-static __always_inline void __cmask_clear(struct scx_cmask __arena *m, u32 cid)
+static __always_inline void __cmask_clear(u32 cid, struct scx_cmask __arena *m)
{
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return;
- *__cmask_word(m, cid) &= ~BIT_U64(cid & 63);
+ *__cmask_word(cid, m) &= ~BIT_U64(cid & 63);
}
-static __always_inline bool __cmask_test_and_set(struct scx_cmask __arena *m, u32 cid)
+static __always_inline bool __cmask_test_and_set(u32 cid, struct scx_cmask __arena *m)
{
u64 bit = BIT_U64(cid & 63);
u64 __arena *w;
u64 prev;
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return false;
- w = __cmask_word(m, cid);
+ w = __cmask_word(cid, m);
prev = *w & bit;
*w |= bit;
return prev;
}
-static __always_inline bool __cmask_test_and_clear(struct scx_cmask __arena *m, u32 cid)
+static __always_inline bool __cmask_test_and_clear(u32 cid, struct scx_cmask __arena *m)
{
u64 bit = BIT_U64(cid & 63);
u64 __arena *w;
u64 prev;
- if (!__cmask_contains(m, cid))
+ if (!__cmask_contains(cid, m))
return false;
- w = __cmask_word(m, cid);
+ w = __cmask_word(cid, m);
prev = *w & bit;
*w &= ~bit;
return prev;
@@ -671,7 +671,7 @@ static __always_inline void cmask_from_cpumask(struct scx_cmask __arena *m,
continue;
cid = scx_bpf_cpu_to_cid(cpu);
if (cid >= 0)
- __cmask_set(m, cid);
+ __cmask_set(cid, m);
}
}
diff --git a/tools/sched_ext/scx_qmap.bpf.c b/tools/sched_ext/scx_qmap.bpf.c
index 8a2d6a8ebd8e..fd9a82a67627 100644
--- a/tools/sched_ext/scx_qmap.bpf.c
+++ b/tools/sched_ext/scx_qmap.bpf.c
@@ -214,7 +214,7 @@ static s32 pick_direct_dispatch_cid(struct task_struct *p, s32 prev_cid,
if (!always_enq_immed && p->nr_cpus_allowed == 1)
return prev_cid;
- if (cmask_test_and_clear(qa_idle_cids, prev_cid))
+ if (cmask_test_and_clear(prev_cid, qa_idle_cids))
return prev_cid;
cid = prev_cid;
@@ -224,7 +224,7 @@ static s32 pick_direct_dispatch_cid(struct task_struct *p, s32 prev_cid,
barrier_var(cid);
if (cid >= nr_cids)
return -1;
- if (cmask_test_and_clear(qa_idle_cids, cid))
+ if (cmask_test_and_clear(cid, qa_idle_cids))
return cid;
}
return -1;
@@ -534,7 +534,7 @@ static bool dispatch_highpri(bool from_timer)
if (!(taskc = lookup_task_ctx(p)))
return false;
- if (cmask_test(&taskc->cpus_allowed, this_cid))
+ if (cmask_test(this_cid, &taskc->cpus_allowed))
cid = this_cid;
else
cid = cmask_next_set_wrap(&taskc->cpus_allowed,
@@ -656,7 +656,7 @@ void BPF_STRUCT_OPS(qmap_dispatch, s32 cid, struct task_struct *prev)
* document this class of issue -- other schedulers
* seeing similar warnings can use this as a reference.
*/
- if (!cmask_test(&taskc->cpus_allowed, cid))
+ if (!cmask_test(cid, &taskc->cpus_allowed))
scx_bpf_kick_cid(scx_bpf_task_cid(p), 0);
batch--;
@@ -913,9 +913,9 @@ void BPF_STRUCT_OPS(qmap_update_idle, s32 cid, bool idle)
{
QMAP_TOUCH_ARENA();
if (idle)
- cmask_set(qa_idle_cids, cid);
+ cmask_set(cid, qa_idle_cids);
else
- cmask_clear(qa_idle_cids, cid);
+ cmask_clear(cid, qa_idle_cids);
}
void BPF_STRUCT_OPS(qmap_set_cmask, struct task_struct *p,
--
2.54.0
next prev parent reply other threads:[~2026-06-04 2:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 2:00 [PATCHSET v2 sched_ext/for-7.2] sched_ext: cid/cmask interface prep Tejun Heo
2026-06-04 2:00 ` [PATCH 1/4] sched_ext: Order single-cid cmask helpers as (cid, mask) Tejun Heo
2026-06-04 2:00 ` Tejun Heo [this message]
2026-06-04 2:00 ` [PATCH 3/4] sched_ext: Add scx_cmask_test() and scx_cmask_for_each_cid() Tejun Heo
2026-06-04 2:10 ` sashiko-bot
2026-06-04 2:00 ` [PATCH 4/4] sched_ext: Make scx_bpf_kick_cid() return s32 Tejun Heo
2026-06-04 6:18 ` [PATCHSET v2 sched_ext/for-7.2] sched_ext: cid/cmask interface prep Andrea Righi
2026-06-04 8:32 ` Tejun Heo
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