linux-kernel - [PATCH v2 1/5] sched_ext: Implement scx_rq_clock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241202043849.1465664-2-changwoo@igalia.com>
Date: Mon,  2 Dec 2024 13:38:45 +0900
From: Changwoo Min <multics69@...il.com>
To: tj@...nel.org,
	void@...ifault.com,
	mingo@...hat.com,
	peterz@...radead.org
Cc: changwoo@...lia.com,
	kernel-dev@...lia.com,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/5] sched_ext: Implement scx_rq_clock_update/stale()

scx_rq_clock_update() and scx_rq_clock_stale() manage the status of an
rq clock. scx_rq_clock_update() keeps the rq clock in memory and its
status valid. scx_rq_clock_stale() invalidates the current rq clock
not to use the cached rq clock.

Signed-off-by: Changwoo Min <changwoo@...lia.com>
---
 kernel/sched/sched.h | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 76f5f53a645f..09d5a64f78ce 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -754,6 +754,7 @@ enum scx_rq_flags {
 	SCX_RQ_BAL_PENDING	= 1 << 2, /* balance hasn't run yet */
 	SCX_RQ_BAL_KEEP		= 1 << 3, /* balance decided to keep current */
 	SCX_RQ_BYPASSING	= 1 << 4,
+	SCX_RQ_CLK_VALID	= 1 << 5, /* RQ clock is fresh and valid */
 
 	SCX_RQ_IN_WAKEUP	= 1 << 16,
 	SCX_RQ_IN_BALANCE	= 1 << 17,
@@ -766,8 +767,9 @@ struct scx_rq {
 	unsigned long		ops_qseq;
 	u64			extra_enq_flags;	/* see move_task_to_local_dsq() */
 	u32			nr_running;
-	u32			flags;
 	u32			cpuperf_target;		/* [0, SCHED_CAPACITY_SCALE] */
+	u64			clock;			/* cached per-rq clock -- see scx_bpf_clock_get_ns() */
+	u32			flags;
 	bool			cpu_released;
 	cpumask_var_t		cpus_to_kick;
 	cpumask_var_t		cpus_to_kick_if_idle;
@@ -1353,6 +1355,24 @@ static inline void rq_set_donor(struct rq *rq, struct task_struct *t)
 	/* Do nothing */
 }
 
+#ifdef CONFIG_SCHED_CLASS_EXT
+static inline void scx_rq_clock_update(struct rq *rq, u64 clock)
+{
+	rq->scx.clock = clock;
+	rq->scx.flags |= SCX_RQ_CLK_VALID;
+}
+
+static inline void scx_rq_clock_stale(struct rq *rq)
+{
+	rq->scx.flags &= ~SCX_RQ_CLK_VALID;
+}
+
+#else
+static inline void scx_rq_clock_update(struct rq *rq, u64 clock) {}
+static inline void scx_rq_clock_stale(struct rq *rq) {}
+
+#endif /* CONFIG_SCHED_CLASS_EXT */
+
 #ifdef CONFIG_SCHED_CORE
 static inline struct cpumask *sched_group_span(struct sched_group *sg);
 
-- 
2.47.1