From patchwork Thu Nov 25 16:08:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 12639491 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 32193C433FE for ; Thu, 25 Nov 2021 16:10:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id AD6CB6B0075; Thu, 25 Nov 2021 11:09:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A86136B007D; Thu, 25 Nov 2021 11:09:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9277C6B007E; Thu, 25 Nov 2021 11:09:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0160.hostedemail.com [216.40.44.160]) by kanga.kvack.org (Postfix) with ESMTP id 84C156B0075 for ; Thu, 25 Nov 2021 11:09:45 -0500 (EST) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4C6908DA3A for ; Thu, 25 Nov 2021 16:09:35 +0000 (UTC) X-FDA: 78847937868.07.D7B5906 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf13.hostedemail.com (Postfix) with ESMTP id 437221055026 for ; Thu, 25 Nov 2021 16:08:36 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id B6BC561107; Thu, 25 Nov 2021 16:08:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637856519; bh=d+bFdpUIyO9jw/UFdit4nDOhOAOS+ttW7MZ7tgg4pBI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iTXjk+20j6QZHx8Guqt2ByWB4B/tpnqFKGdZazmyLAqr3eHorcC3hXbXsYpz7Y0Ik seG5ANdEfb3nh9qB9unfRNE0yrmVofHPmQ+avYu110ju2mnG2pPxuEPeDjwmQmCq63 v3ujr7anHYPwvQ6LQoPnDc3tMjxXg9a1N9PkRpxNRduYq0hp080DHMSEaM8+hbb7tC eejZKNWVXJPKNcnN+uTtEXVZ/sa8fXWHp/DX+gjl3/Nsk5JprQiIENwd6FFsM/FkXM WeogogbxsLUexJ+lR6y3ZSGyd9Oh0BaoVyak+ce9ItbxWsLJ8nDdP/o98UsLNXatai O/XFbTzOIO7sg== From: SeongJae Park To: akpm@linux-foundation.org Cc: john.stultz@linaro.org, tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park Subject: [PATCH v2 1/2] timers: Implement usleep_idle_range() Date: Thu, 25 Nov 2021 16:08:29 +0000 Message-Id: <20211125160830.30153-2-sj@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211125160830.30153-1-sj@kernel.org> References: <20211125160830.30153-1-sj@kernel.org> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 437221055026 X-Stat-Signature: jrhjzysuqh16qifowga7q6gb6zmocgk8 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=iTXjk+20; spf=pass (imf13.hostedemail.com: domain of sj@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-HE-Tag: 1637856516-13399 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. Signed-off-by: SeongJae Park --- 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); From patchwork Thu Nov 25 16:08:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 12639489 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 C0B0CC433F5 for ; Thu, 25 Nov 2021 16:09:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B252C6B007B; Thu, 25 Nov 2021 11:08:54 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AD4C56B007D; Thu, 25 Nov 2021 11:08:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9C48E6B007E; Thu, 25 Nov 2021 11:08:54 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0154.hostedemail.com [216.40.44.154]) by kanga.kvack.org (Postfix) with ESMTP id 8E9826B007B for ; Thu, 25 Nov 2021 11:08:54 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id EA9E98D8E3 for ; Thu, 25 Nov 2021 16:08:43 +0000 (UTC) X-FDA: 78847935726.15.B1A8A83 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf28.hostedemail.com (Postfix) with ESMTP id 2A51990000A5 for ; Thu, 25 Nov 2021 16:08:43 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 92F4860524; Thu, 25 Nov 2021 16:08:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637856522; bh=3UuzhmSP/V3v920tpSUyBSyVCTZdS6flxK4IwxjCSag=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HTBnD1Z8JkUNt2GshUi4VmmLZbfw6da+Ad+2iDfwk74ir1qlXhaQOGt6BAVMdIswa Cj9Wm4arsj+c80ZP1JWFBchKlPRHHg1bk2pQXkTDN0HRNm6WCHVdk6Xgha0QSyj+SV WzyWHaGKuZytFxkHVaDQpzXfzkGE+9uWojvj/3vG45KNEtbC6vRhOZGtYk+PBwaY7K IUyJb9u4vMR/2RhmjBr29rRigG6cBhbvGNtooLxtZJRVBl3+wrCmnfaoJHAqQKubTx 3hRDN3Ga3gN6CQcd3DHbow8JQiGtEzEp+nfipsfi7LBcnqkH0PGAR1bJqyH4f3+BPn 5EguI4QXF83Vg== From: SeongJae Park To: akpm@linux-foundation.org Cc: john.stultz@linaro.org, tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park , stable@vger.kernel.org Subject: [PATCH v2 2/2] mm/damon/core: Fix fake load reports due to uninterruptible sleeps Date: Thu, 25 Nov 2021 16:08:30 +0000 Message-Id: <20211125160830.30153-3-sj@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211125160830.30153-1-sj@kernel.org> References: <20211125160830.30153-1-sj@kernel.org> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 2A51990000A5 X-Stat-Signature: mqydattoku7idnxiy5ado8b4pykt99gx Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=HTBnD1Z8; spf=pass (imf28.hostedemail.com: domain of sj@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=sj@kernel.org; dmarc=pass (policy=none) header.from=kernel.org X-HE-Tag: 1637856523-953128 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: Because DAMON sleeps in uninterruptible mode, /proc/loadavg reports fake load while DAMON is turned on, though it is doing nothing. This can confuse users[1]. To avoid the case, this commit makes DAMON sleeps in idle mode. [1] https://lore.kernel.org/all/11868371.O9o76ZdvQC@natalenko.name/ Fixes: 2224d8485492 ("mm: introduce Data Access MONitor (DAMON)") Reported-by: Oleksandr Natalenko Signed-off-by: SeongJae Park Cc: # 5.15.x --- mm/damon/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index daacd9536c7c..8cd8fddc931e 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -979,9 +979,9 @@ static unsigned long damos_wmark_wait_us(struct damos *scheme) static void kdamond_usleep(unsigned long usecs) { if (usecs > 100 * 1000) - schedule_timeout_interruptible(usecs_to_jiffies(usecs)); + schedule_timeout_idle(usecs_to_jiffies(usecs)); else - usleep_range(usecs, usecs + 1); + usleep_idle_range(usecs, usecs + 1); } /* Returns negative error code if it's not activated but should return */ @@ -1036,7 +1036,7 @@ static int kdamond_fn(void *data) ctx->callback.after_sampling(ctx)) done = true; - usleep_range(ctx->sample_interval, ctx->sample_interval + 1); + kdamond_usleep(ctx->sample_interval); if (ctx->primitive.check_accesses) max_nr_accesses = ctx->primitive.check_accesses(ctx);