From nobody Sun Feb 8 15:08:35 2026 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3DC715E96; Sun, 18 Aug 2024 06:23:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723962193; cv=none; b=A4VU8P3gpDJT20CnYOtIFn8G7UIZsd7X8HwT0MlYuQqmx6+hnlWoHorVyIU7ldrpb9QcR7Nt391aQpbjaVs9srclJdookhU4MOpPOLl91SeKS/1PcF7D9HgdOnXkJpKYmImYI4TxRfFtW5YFwNlG0PBXnQRiWmndv4ZeYWYA8t0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723962193; c=relaxed/simple; bh=lvRgzYCEnhZBCm9i7N4I4IXs4JCtsczkMXRSeucuMdk=; h=Date:From:To:Subject:Cc:In-Reply-To:References:MIME-Version: Message-ID:Content-Type; b=u3p6yO4V1jUNqA7B3Jgt/wflFZZaEa36gVuSVWDpUMxhD29vV7IF4M46BhRbwq4v6V1UwyXJyRAvxa3/cbyRlglj7knHG9ztQ2xResTVz5niGH8KLplhfSju3chPqc1LSWE0ndYj0LCTQubA0TugMy2VAQMN3zV2SQDfNJp65qs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Ni1JbG4O; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=ChtoDEfs; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Ni1JbG4O"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="ChtoDEfs" Date: Sun, 18 Aug 2024 06:23:07 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1723962187; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+w3UgpyFpI657egP/Z0l+yUbB0FR1/oKS5o3vowoh0g=; b=Ni1JbG4OO5zEfYHCuZr3pSRQhZ0FlpxXQSFA+wUDraXTNdtJncP3OIKdCJaJ+swfLT8FDf r2XXuAWLOSKWaF8wf98Ci6nJbM8lQMagN3MFjZnWRhaLiIuCi5Ken04gSNiwrjfYiP8Cve B8nbw2teM6leMkT0j2LXotAAhNoN4CL8uEqPfbYQ07tF13EVIW6xG5eCyVj/+hHj8yoGGk FVEGOcl3CvqrSIEiS47RQD88+7CA9EpK3gU83k5gpA91IDpCab/ybkDmOot360IDmznvin ygX/lHweZq2aqqpd2U3WvYZ/ZoNNUggS1V9z4HGRDKkl2xExpAZ10xM3AXfSRA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1723962187; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=+w3UgpyFpI657egP/Z0l+yUbB0FR1/oKS5o3vowoh0g=; b=ChtoDEfsqxNTFfJhmiHGCaXV6UQDl1XIsSJQQgol6CknK+1On1lvoq6wcZZMmCDAaFjS6g go+V/AMXlJEe6bBA== From: "tip-bot2 for Peter Zijlstra" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/fair: Implement DELAY_ZERO Cc: "Peter Zijlstra (Intel)" , Valentin Schneider , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20240727105030.403750550@infradead.org> References: <20240727105030.403750550@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <172396218743.2215.1544441241531263872.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Precedence: bulk Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable The following commit has been merged into the sched/core branch of tip: Commit-ID: 54a58a78779169f9c92a51facf6de7ce94962328 Gitweb: https://git.kernel.org/tip/54a58a78779169f9c92a51facf6de7ce9= 4962328 Author: Peter Zijlstra AuthorDate: Thu, 23 May 2024 12:26:06 +02:00 Committer: Peter Zijlstra CommitterDate: Sat, 17 Aug 2024 11:06:44 +02:00 sched/fair: Implement DELAY_ZERO 'Extend' DELAY_DEQUEUE by noting that since we wanted to dequeued them at the 0-lag point, truncate lag (eg. don't let them earn positive lag). Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Tested-by: Valentin Schneider Link: https://lkml.kernel.org/r/20240727105030.403750550@infradead.org --- kernel/sched/fair.c | 20 ++++++++++++++++++-- kernel/sched/features.h | 3 +++ 2 files changed, 21 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index da5065a..1a59339 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5447,8 +5447,11 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_e= ntity *se, int flags) if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) !=3D DEQUEUE_SAVE) update_min_vruntime(cfs_rq); =20 - if (flags & DEQUEUE_DELAYED) + if (flags & DEQUEUE_DELAYED) { se->sched_delayed =3D 0; + if (sched_feat(DELAY_ZERO) && se->vlag > 0) + se->vlag =3D 0; + } =20 if (cfs_rq->nr_running =3D=3D 0) update_idle_cfs_rq_clock_pelt(cfs_rq); @@ -5527,7 +5530,6 @@ pick_next_entity(struct rq *rq, struct cfs_rq *cfs_rq) dequeue_entities(rq, se, DEQUEUE_SLEEP | DEQUEUE_DELAYED); SCHED_WARN_ON(se->sched_delayed); SCHED_WARN_ON(se->on_rq); - return NULL; } return se; @@ -6825,6 +6827,20 @@ requeue_delayed_entity(struct sched_entity *se) SCHED_WARN_ON(!se->sched_delayed); SCHED_WARN_ON(!se->on_rq); =20 + if (sched_feat(DELAY_ZERO)) { + update_entity_lag(cfs_rq, se); + if (se->vlag > 0) { + cfs_rq->nr_running--; + if (se !=3D cfs_rq->curr) + __dequeue_entity(cfs_rq, se); + se->vlag =3D 0; + place_entity(cfs_rq, se, 0); + if (se !=3D cfs_rq->curr) + __enqueue_entity(cfs_rq, se); + cfs_rq->nr_running++; + } + } + se->sched_delayed =3D 0; } =20 diff --git a/kernel/sched/features.h b/kernel/sched/features.h index 1feaa7b..7fdeb55 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -34,8 +34,11 @@ SCHED_FEAT(CACHE_HOT_BUDDY, true) * By delaying the dequeue for non-eligible tasks, they remain in the * competition and can burn off their negative lag. When they get selected * they'll have positive lag by definition. + * + * DELAY_ZERO clips the lag on dequeue (or wakeup) to 0. */ SCHED_FEAT(DELAY_DEQUEUE, true) +SCHED_FEAT(DELAY_ZERO, true) =20 /* * Allow wakeup-time preemption of the current task: