From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 159B6C43387 for ; Thu, 10 Jan 2019 10:12:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D79AC2173B for ; Thu, 10 Jan 2019 10:12:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728179AbfAJKMk (ORCPT ); Thu, 10 Jan 2019 05:12:40 -0500 Received: from metis.ext.pengutronix.de ([85.220.165.71]:47069 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727257AbfAJKMh (ORCPT ); Thu, 10 Jan 2019 05:12:37 -0500 Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1ghXKF-0003ie-6H; Thu, 10 Jan 2019 11:12:35 +0100 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.91) (envelope-from ) id 1ghXKE-0002UY-2L; Thu, 10 Jan 2019 11:12:34 +0100 From: Oleksij Rempel To: Greg Kroah-Hartman , Jiri Slaby Cc: Oleksij Rempel , Pengutronix Kernel Team , linux-kernel@vger.kernel.org Subject: [PATCH v1 3/3] drivers/tty: increase priority for tty_buffer_worker Date: Thu, 10 Jan 2019 11:12:32 +0100 Message-Id: <20190110101232.9398-4-o.rempel@pengutronix.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190110101232.9398-1-o.rempel@pengutronix.de> References: <20190110101232.9398-1-o.rempel@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org sched_priority = 1 is enough to dramatically reduce latency on have system load produced by tasks with default user space prio. Signed-off-by: Oleksij Rempel --- drivers/tty/tty_buffer.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 18bd7f48a319..7cf42f6570a0 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -13,11 +13,13 @@ #include #include #include +#include #include #include #include #include #include +#include #define MIN_TTYB_SIZE 256 @@ -567,7 +569,15 @@ bool tty_buffer_queue_work(struct tty_port *port) void tty_buffer_init_kthread(void) { - kthread_run(kthread_worker_fn, &tty_buffer_worker, "tty"); + struct sched_param param = { .sched_priority = 1 }; + struct task_struct *kworker_task; + + kworker_task = kthread_run(kthread_worker_fn, &tty_buffer_worker, "tty"); + if (IS_ERR(kworker_task)) { + pr_err("failed to create message pump task\n"); + return; + } + sched_setscheduler(kworker_task, SCHED_FIFO, ¶m); } /** -- 2.19.1