From: "tip-bot2 for Yunfeng Ye" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Yunfeng Ye <yeyunfeng@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: timers/core] tick/sched: Release seqcount before invoking calc_load_global()
Date: Thu, 19 Nov 2020 09:55:07 -0000 [thread overview]
Message-ID: <160577970772.11244.568999884653345712.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20201117132006.660902274@linutronix.de>
The following commit has been merged into the timers/core branch of tip:
Commit-ID: 896b969e6732b68ee3c12ae4e1aeddf5db99bc46
Gitweb: https://git.kernel.org/tip/896b969e6732b68ee3c12ae4e1aeddf5db99bc46
Author: Yunfeng Ye <yeyunfeng@huawei.com>
AuthorDate: Tue, 17 Nov 2020 14:19:48 +01:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Thu, 19 Nov 2020 10:48:29 +01:00
tick/sched: Release seqcount before invoking calc_load_global()
calc_load_global() does not need the sequence count protection.
[ tglx: Split it up properly and added comments ]
Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201117132006.660902274@linutronix.de
---
kernel/time/tick-sched.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 306adeb..33c897b 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -20,6 +20,7 @@
#include <linux/sched/clock.h>
#include <linux/sched/stat.h>
#include <linux/sched/nohz.h>
+#include <linux/sched/loadavg.h>
#include <linux/module.h>
#include <linux/irq_work.h>
#include <linux/posix-timers.h>
@@ -107,7 +108,8 @@ static void tick_do_update_jiffies64(ktime_t now)
tick_period);
}
- do_timer(ticks);
+ /* Advance jiffies to complete the jiffies_seq protected job */
+ jiffies_64 += ticks;
/*
* Keep the tick_next_period variable up to date. WRITE_ONCE()
@@ -116,7 +118,15 @@ static void tick_do_update_jiffies64(ktime_t now)
WRITE_ONCE(tick_next_period,
ktime_add(last_jiffies_update, tick_period));
+ /*
+ * Release the sequence count. calc_global_load() below is not
+ * protected by it, but jiffies_lock needs to be held to prevent
+ * concurrent invocations.
+ */
write_seqcount_end(&jiffies_seq);
+
+ calc_global_load();
+
raw_spin_unlock(&jiffies_lock);
update_wall_time();
}
next prev parent reply other threads:[~2020-11-19 9:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-17 13:19 [patch 0/7] tick: Cleanups and reduce jiffies_seq held times Thomas Gleixner
2020-11-17 13:19 ` [patch 1/7] tick/broadcast: Serialize access to tick_next_period Thomas Gleixner
2020-11-19 9:55 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-11-17 13:19 ` [patch 2/7] tick: Document protections for tick related data Thomas Gleixner
2020-11-19 9:55 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-11-17 13:19 ` [patch 3/7] tick/sched: Use tick_next_period for lockless quick check Thomas Gleixner
2020-11-19 9:55 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-11-17 13:19 ` [patch 4/7] tick/sched: Reduce seqcount held scope in tick_do_update_jiffies64() Thomas Gleixner
2020-11-19 9:55 ` [tip: timers/core] " tip-bot2 for Yunfeng Ye
2020-11-17 13:19 ` [patch 5/7] tick/sched: Optimize tick_do_update_jiffies64() further Thomas Gleixner
2020-11-19 9:55 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2020-11-17 13:19 ` [patch 6/7] tick/sched: Release seqcount before invoking calc_load_global() Thomas Gleixner
2020-11-19 9:55 ` tip-bot2 for Yunfeng Ye [this message]
2020-11-17 13:19 ` [patch 7/7] tick: Get rid of tick_period Thomas Gleixner
2020-11-19 9:55 ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=160577970772.11244.568999884653345712.tip-bot2@tip-bot2 \
--to=tip-bot2@linutronix.de \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
--cc=yeyunfeng@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).