From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 35FEC44CAC2; Mon, 20 Apr 2026 13:30:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776691815; cv=none; b=BIMceYuXjbvrrFGQrDHFPdVtkV01dYhvWulGBZBjDPcfDOotiEXA1whHdhN0OxDzn/ZeJsvyOU2Nh7s1G8nSkLuARnKfmuZ8LTtz2/zVN14fLzVjeDEj5yif6x6ljSA59lk42MhUGZt6KNmQxIc/dUoj5S3/dn4aiU17N3NidUw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776691815; c=relaxed/simple; bh=+9tLxTbJEvLfYKwLP48Py/JtNZ4I5NlgVQExqjeMhLE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dFnQpP3Ag6qE4WoJxNT/tYw6LaQyXd+pftk0qC/w9HRp0HoGKMbO1h2xxV0sLP52eflphMgh3Imm/nn//nGyR8A7a9LwL7p1ZHTHePD7PK4vs/0JiEA2MPFyJk1PQ4cY0NeagtzwCucyQvFcfuTKlLXvOa1JlrLuu2h6muzLT6k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mAgknYtY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mAgknYtY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FDACC19425; Mon, 20 Apr 2026 13:30:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776691815; bh=+9tLxTbJEvLfYKwLP48Py/JtNZ4I5NlgVQExqjeMhLE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mAgknYtYDousKKY6q3CaNdIp3cT8u5VXkE5zQNvhdFPH1/xV6K+0fWPieEni+qAPb 40SD0p/Lj0+F4DRhP83ZJ8ZvIY9F8MvG3rdLUkpeBiUtzEqNGwzhxEPvbTwZgLw8Yh yOWTwZozIxVJU00GxuFPUMDZFsxUktR7yIau3ii7i38Rqpzok65ZUMbwyFjQ7YQSBx yfUmpgPtxTufNajBEuyiQC95edZdyl6Dv3ifWy6vosNwEVf62BzASGSuemli1N3+lS E0Fa9giH5b4ajuVO/qBgNeEAyd8DU67e1Fg7/QlYZCvrfzcrVQrLAiB8djVVu+cUdu C2G0h83nknucw== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Peter Zijlstra , John Stultz , Juri Lelli , Sasha Levin , mingo@redhat.com, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 6.18] sched/deadline: Use revised wakeup rule for dl_server Date: Mon, 20 Apr 2026 09:20:05 -0400 Message-ID: <20260420132314.1023554-211-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420132314.1023554-1-sashal@kernel.org> References: <20260420132314.1023554-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.18.23 Content-Transfer-Encoding: 8bit From: Peter Zijlstra [ Upstream commit 14a857056466be9d3d907a94e92a704ac1be149b ] John noted that commit 115135422562 ("sched/deadline: Fix 'stuck' dl_server") unfixed the issue from commit a3a70caf7906 ("sched/deadline: Fix dl_server behaviour"). The issue in commit 115135422562 was for wakeups of the server after the deadline; in which case you *have* to start a new period. The case for a3a70caf7906 is wakeups before the deadline. Now, because the server is effectively running a least-laxity policy, it means that any wakeup during the runnable phase means dl_entity_overflow() will be true. This means we need to adjust the runtime to allow it to still run until the existing deadline expires. Use the revised wakeup rule for dl_defer entities. Fixes: 115135422562 ("sched/deadline: Fix 'stuck' dl_server") Reported-by: John Stultz Signed-off-by: Peter Zijlstra (Intel) Acked-by: Juri Lelli Tested-by: John Stultz Link: https://patch.msgid.link/20260404102244.GB22575@noisy.programming.kicks-ass.net Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: Error: Failed to generate final synthesis kernel/sched/deadline.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 72499cf2a1db5..d5052f238adf7 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1036,7 +1036,7 @@ static void update_dl_entity(struct sched_dl_entity *dl_se) if (dl_time_before(dl_se->deadline, rq_clock(rq)) || dl_entity_overflow(dl_se, rq_clock(rq))) { - if (unlikely(!dl_is_implicit(dl_se) && + if (unlikely((!dl_is_implicit(dl_se) || dl_se->dl_defer) && !dl_time_before(dl_se->deadline, rq_clock(rq)) && !is_dl_boosted(dl_se))) { update_dl_revised_wakeup(dl_se, rq); -- 2.53.0