From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758023AbeD0Mjx (ORCPT ); Fri, 27 Apr 2018 08:39:53 -0400 Received: from terminus.zytor.com ([198.137.202.136]:41541 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757373AbeD0Mjv (ORCPT ); Fri, 27 Apr 2018 08:39:51 -0400 Date: Fri, 27 Apr 2018 05:39:45 -0700 From: tip-bot for Sebastian Andrzej Siewior Message-ID: Cc: hpa@zytor.com, mingo@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, bigeasy@linutronix.de, bsingharora@gmail.com Reply-To: mingo@kernel.org, hpa@zytor.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, bigeasy@linutronix.de, bsingharora@gmail.com In-Reply-To: <20180423161024.6710-1-bigeasy@linutronix.de> References: <20180423161024.6710-1-bigeasy@linutronix.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:locking/core] delayacct: Use raw_spinlocks Git-Commit-ID: 02acc80d19edb0d5684c997b2004ad19f9f5236e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 02acc80d19edb0d5684c997b2004ad19f9f5236e Gitweb: https://git.kernel.org/tip/02acc80d19edb0d5684c997b2004ad19f9f5236e Author: Sebastian Andrzej Siewior AuthorDate: Mon, 23 Apr 2018 18:10:23 +0200 Committer: Thomas Gleixner CommitDate: Fri, 27 Apr 2018 14:34:51 +0200 delayacct: Use raw_spinlocks try_to_wake_up() might invoke delayacct_blkio_end() while holding the pi_lock (which is a raw_spinlock_t). delayacct_blkio_end() acquires task_delay_info.lock which is a spinlock_t. This causes a might sleep splat on -RT where non raw spinlocks are converted to 'sleeping' spinlocks. task_delay_info.lock is only held for a short amount of time so it's not a problem latency wise to make convert it to a raw spinlock. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Balbir Singh Link: https://lkml.kernel.org/r/20180423161024.6710-1-bigeasy@linutronix.de --- include/linux/delayacct.h | 2 +- kernel/delayacct.c | 17 +++++++++-------- 2 files changed, 10 insertions(+), 9 deletions(-) diff --git a/include/linux/delayacct.h b/include/linux/delayacct.h index 5e335b6203f4..e6c0448ebcc7 100644 --- a/include/linux/delayacct.h +++ b/include/linux/delayacct.h @@ -29,7 +29,7 @@ #ifdef CONFIG_TASK_DELAY_ACCT struct task_delay_info { - spinlock_t lock; + raw_spinlock_t lock; unsigned int flags; /* Private per-task flags */ /* For each stat XXX, add following, aligned appropriately diff --git a/kernel/delayacct.c b/kernel/delayacct.c index e2764d767f18..ca8ac2824f0b 100644 --- a/kernel/delayacct.c +++ b/kernel/delayacct.c @@ -44,23 +44,24 @@ void __delayacct_tsk_init(struct task_struct *tsk) { tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL); if (tsk->delays) - spin_lock_init(&tsk->delays->lock); + raw_spin_lock_init(&tsk->delays->lock); } /* * Finish delay accounting for a statistic using its timestamps (@start), * accumalator (@total) and @count */ -static void delayacct_end(spinlock_t *lock, u64 *start, u64 *total, u32 *count) +static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, + u32 *count) { s64 ns = ktime_get_ns() - *start; unsigned long flags; if (ns > 0) { - spin_lock_irqsave(lock, flags); + raw_spin_lock_irqsave(lock, flags); *total += ns; (*count)++; - spin_unlock_irqrestore(lock, flags); + raw_spin_unlock_irqrestore(lock, flags); } } @@ -127,7 +128,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ - spin_lock_irqsave(&tsk->delays->lock, flags); + raw_spin_lock_irqsave(&tsk->delays->lock, flags); tmp = d->blkio_delay_total + tsk->delays->blkio_delay; d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp; tmp = d->swapin_delay_total + tsk->delays->swapin_delay; @@ -137,7 +138,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) d->blkio_count += tsk->delays->blkio_count; d->swapin_count += tsk->delays->swapin_count; d->freepages_count += tsk->delays->freepages_count; - spin_unlock_irqrestore(&tsk->delays->lock, flags); + raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); return 0; } @@ -147,10 +148,10 @@ __u64 __delayacct_blkio_ticks(struct task_struct *tsk) __u64 ret; unsigned long flags; - spin_lock_irqsave(&tsk->delays->lock, flags); + raw_spin_lock_irqsave(&tsk->delays->lock, flags); ret = nsec_to_clock_t(tsk->delays->blkio_delay + tsk->delays->swapin_delay); - spin_unlock_irqrestore(&tsk->delays->lock, flags); + raw_spin_unlock_irqrestore(&tsk->delays->lock, flags); return ret; }