linux-kernel - [RFC 1/1] sched: Deprecate DOUBLE

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Message-ID: <20240308052304.1835792-2-vishalc@linux.ibm.com>
Date: Fri,  8 Mar 2024 10:53:04 +0530
From: Vishal Chourasia <vishalc@...ux.ibm.com>
To: peterz@...radead.org, linux-kernel@...r.kernel.org
Cc: Vishal Chourasia <vishalc@...ux.ibm.com>
Subject: [RFC 1/1] sched: Deprecate DOUBLE_TICK feature

The DOUBLE_TICK feature, introduced to manage the interaction between
periodic and high-resolution timer ticks, has become obsolete following
the removal of the check_preempt_tick method in commit 5e963f2bd465
("sched/fair: Commit to EEVDF"). This change rendered the DOUBLE_TICK
check in entity_tick pointless, as it no longer influences scheduling
decisions.

This commit removes the DOUBLE_TICK feature flag, simplifying the
scheduler code and eliminating a now-unnecessary check.

Signed-off-by: Vishal Chourasia <vishalc@...ux.ibm.com>
---
 kernel/sched/fair.c     | 6 ------
 kernel/sched/features.h | 1 -
 2 files changed, 7 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 533547e3c90a..73e1372d1a0d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5510,12 +5510,6 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
 		resched_curr(rq_of(cfs_rq));
 		return;
 	}
-	/*
-	 * don't let the period tick interfere with the hrtick preemption
-	 */
-	if (!sched_feat(DOUBLE_TICK) &&
-			hrtimer_active(&rq_of(cfs_rq)->hrtick_timer))
-		return;
 #endif
 }
 
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 143f55df890b..f2671bf8d6ab 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -28,7 +28,6 @@ SCHED_FEAT(WAKEUP_PREEMPTION, true)
 
 SCHED_FEAT(HRTICK, false)
 SCHED_FEAT(HRTICK_DL, false)
-SCHED_FEAT(DOUBLE_TICK, false)
 
 /*
  * Decrement CPU capacity based on time not spent running tasks
-- 
2.43.0