From patchwork Fri Nov 26 14:50:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 12640941 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5EDBEC433F5 for ; Fri, 26 Nov 2021 14:51:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DB4046B007B; Fri, 26 Nov 2021 09:50:38 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D64DC6B007D; Fri, 26 Nov 2021 09:50:38 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C2C566B007E; Fri, 26 Nov 2021 09:50:38 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0169.hostedemail.com [216.40.44.169]) by kanga.kvack.org (Postfix) with ESMTP id B61BF6B007B for ; Fri, 26 Nov 2021 09:50:38 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 751B78248D52 for ; Fri, 26 Nov 2021 14:50:28 +0000 (UTC) X-FDA: 78851367294.20.804FA03 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf26.hostedemail.com (Postfix) with ESMTP id 44DA220019C8 for ; Fri, 26 Nov 2021 14:50:26 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C571DB827FD; Fri, 26 Nov 2021 14:50:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6469C9305D; Fri, 26 Nov 2021 14:50:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637938224; bh=s1q37RCQIwajhGA+DkImquqdXKMhY8FQHPrpGfdbiDM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oaKdSrXIxZ43L2Xkz38OnzQSwZgTzRECeokkA4sgMv7PvPo4C6lY/o/J1+BJhWSGl egNGLxcilg6B5KtrBF2Qf+0sX7YpkNW0UIEw5Vdt+l5crsi/3AmmvIXTagwHWfY8zX hcYlolNpfWaUrzJgZV3NGcDjk5JiJ74NyWXSou0Zjg2IEVGDAS8reLgVlxvANkKbLh IE2sDabIvZethf3RVkJ1T9PZJbVLVB4XuKrZETktdh2V8ripkdw6OkCrOqSBaX8TXR Y0fUFVyiEz/X5U0Bx94lyucRUkfPGbAb+Giv1uyOiqoYXgbK2zbYK3EI5NlwOY4D7f bymv0oP1ykmsA== From: SeongJae Park To: akpm@linux-foundation.org Cc: oleksandr@natalenko.name, john.stultz@linaro.org, tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park Subject: [PATCH v3 1/2] timers: Implement usleep_idle_range() Date: Fri, 26 Nov 2021 14:50:14 +0000 Message-Id: <20211126145015.15862-2-sj@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211126145015.15862-1-sj@kernel.org> References: <20211126145015.15862-1-sj@kernel.org> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 44DA220019C8 X-Stat-Signature: 4fcmf3sfmtbfuiwsris8mah667uj1sxj Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=oaKdSrXI; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf26.hostedemail.com: domain of sj@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=sj@kernel.org X-HE-Tag: 1637938226-71462 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Some kernel threads such as DAMON could need to repeatedly sleep in micro seconds level. Because usleep_range() sleeps in uninterruptible state, however, such threads would make /proc/loadavg reports fake load. To help such cases, this commit implements a variant of usleep_range() called usleep_idle_range(). It is same to usleep_range() but sets the state of the current task as TASK_IDLE while sleeping. Suggested-by: Andrew Morton Signed-off-by: SeongJae Park Reviewed-by: Thomas Gleixner --- include/linux/delay.h | 14 +++++++++++++- kernel/time/timer.c | 16 +++++++++------- 2 files changed, 22 insertions(+), 8 deletions(-) diff --git a/include/linux/delay.h b/include/linux/delay.h index 8eacf67eb212..039e7e0c7378 100644 --- a/include/linux/delay.h +++ b/include/linux/delay.h @@ -20,6 +20,7 @@ */ #include +#include extern unsigned long loops_per_jiffy; @@ -58,7 +59,18 @@ void calibrate_delay(void); void __attribute__((weak)) calibration_delay_done(void); void msleep(unsigned int msecs); unsigned long msleep_interruptible(unsigned int msecs); -void usleep_range(unsigned long min, unsigned long max); +void usleep_range_state(unsigned long min, unsigned long max, + unsigned int state); + +static inline void usleep_range(unsigned long min, unsigned long max) +{ + usleep_range_state(min, max, TASK_UNINTERRUPTIBLE); +} + +static inline void usleep_idle_range(unsigned long min, unsigned long max) +{ + usleep_range_state(min, max, TASK_IDLE); +} static inline void ssleep(unsigned int seconds) { diff --git a/kernel/time/timer.c b/kernel/time/timer.c index e3d2c23c413d..85f1021ad459 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -2054,26 +2054,28 @@ unsigned long msleep_interruptible(unsigned int msecs) EXPORT_SYMBOL(msleep_interruptible); /** - * usleep_range - Sleep for an approximate time - * @min: Minimum time in usecs to sleep - * @max: Maximum time in usecs to sleep + * usleep_range_state - Sleep for an approximate time in a given state + * @min: Minimum time in usecs to sleep + * @max: Maximum time in usecs to sleep + * @state: State of the current task that will be while sleeping * * In non-atomic context where the exact wakeup time is flexible, use - * usleep_range() instead of udelay(). The sleep improves responsiveness + * usleep_range_state() instead of udelay(). The sleep improves responsiveness * by avoiding the CPU-hogging busy-wait of udelay(), and the range reduces * power usage by allowing hrtimers to take advantage of an already- * scheduled interrupt instead of scheduling a new one just for this sleep. */ -void __sched usleep_range(unsigned long min, unsigned long max) +void __sched usleep_range_state(unsigned long min, unsigned long max, + unsigned int state) { ktime_t exp = ktime_add_us(ktime_get(), min); u64 delta = (u64)(max - min) * NSEC_PER_USEC; for (;;) { - __set_current_state(TASK_UNINTERRUPTIBLE); + __set_current_state(state); /* Do not return before the requested sleep time has elapsed */ if (!schedule_hrtimeout_range(&exp, delta, HRTIMER_MODE_ABS)) break; } } -EXPORT_SYMBOL(usleep_range); +EXPORT_SYMBOL(usleep_range_state);