From: Joel Fernandes <joel@joelfernandes.org>
To: Huacai Chen <chenhuacai@kernel.org>
Cc: paulmck@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Z qiang <qiang.zhang1211@gmail.com>,
Huacai Chen <chenhuacai@loongson.cn>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Josh Triplett <josh@joshtriplett.org>,
Boqun Feng <boqun.feng@gmail.com>, Ingo Molnar <mingo@kernel.org>,
John Stultz <jstultz@google.com>, Stephen Boyd <sboyd@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, Binbin Zhou <zhoubinbin@loongson.cn>
Subject: Re: [PATCH V4 2/2] rcu: Update jiffies in rcu_cpu_stall_reset()
Date: Wed, 30 Aug 2023 01:04:44 +0000 [thread overview]
Message-ID: <20230830010444.GA33437@google.com> (raw)
In-Reply-To: <CAAhV-H5tYV=ezPY_O7c=sd3DULB6BjoiYnw9nE2EzDFaBHcKPw@mail.gmail.com>
On Mon, Aug 28, 2023 at 11:12:49PM +0800, Huacai Chen wrote:
> Maybe putting
> nr_fqs_jiffies_stall before jiffies_force_qs is better, because I
> think putting an 'int' between two 'long' is wasting space. :)
Though it is a decent suggestion, moving it before jiffies_force_qs does not
make the structure smaller. Trying to outsmart the compiler seems not a good
idea when it is not really packing the structure.
Besides, I am not too worried about 4-byte holes considering the structure is
full of them and that ofl_lock is ____cacheline_internodealigned_in_smp which
adds a giant 55 byte hole to the structure. That should keep you at night if
you are worried about 4 byte holes.
And the total size of the structure on a 64-bit build is 3776 bytes so 4
bytes is about 1/10th of a percent. Puny.
So I'd rather leave nr_fqs_jiffies_stall where it is especially considering
it is more readable where it is. :-)
thanks,
- Joel
>
> Huacai
>
> >
> > Thanks.
next prev parent reply other threads:[~2023-08-30 1:05 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230814020045.51950-1-chenhuacai@loongson.cn>
2023-08-14 2:00 ` [PATCH V4 2/2] rcu: Update jiffies in rcu_cpu_stall_reset() Huacai Chen
2023-08-14 16:15 ` Paul E. McKenney
2023-08-15 6:05 ` Huacai Chen
2023-08-16 3:16 ` Z qiang
2023-08-16 4:53 ` Huacai Chen
2023-08-16 5:09 ` Z qiang
2023-08-16 9:33 ` Huacai Chen
2023-08-16 10:06 ` Z qiang
2023-08-16 12:28 ` Huacai Chen
2023-08-16 15:56 ` Alan Huang
2023-08-16 16:13 ` Huacai Chen
2023-08-16 16:52 ` Alan Huang
2023-08-17 4:04 ` Huacai Chen
2023-08-23 21:41 ` Thomas Gleixner
2023-08-16 19:27 ` Joel Fernandes
2023-08-17 8:06 ` Huacai Chen
2023-08-23 22:03 ` Thomas Gleixner
2023-08-23 22:41 ` Paul E. McKenney
2023-08-24 2:50 ` Huacai Chen
2023-08-24 11:40 ` Paul E. McKenney
2023-08-24 12:40 ` Huacai Chen
2023-08-24 13:24 ` Paul E. McKenney
2023-08-24 15:43 ` Huacai Chen
2023-08-24 18:28 ` Paul E. McKenney
2023-08-25 11:15 ` Huacai Chen
2023-08-25 23:28 ` Joel Fernandes
2023-08-27 3:27 ` Joel Fernandes
2023-08-27 5:50 ` Huacai Chen
2023-08-27 22:11 ` Joel Fernandes
2023-08-28 10:47 ` Paul E. McKenney
2023-08-28 11:30 ` Huacai Chen
2023-08-28 11:54 ` Paul E. McKenney
2023-08-28 13:33 ` Joel Fernandes
2023-08-28 14:02 ` Paul E. McKenney
2023-08-28 14:37 ` Huacai Chen
2023-08-28 14:50 ` Joel Fernandes
2023-08-28 15:12 ` Huacai Chen
2023-08-28 20:47 ` Joel Fernandes
2023-08-29 4:07 ` Huacai Chen
2023-08-29 14:46 ` Joel Fernandes
2023-08-30 4:25 ` Huacai Chen
2023-08-30 10:18 ` Joel Fernandes
2023-08-30 1:04 ` Joel Fernandes [this message]
2023-08-26 1:45 ` Paul E. McKenney
2023-08-24 13:09 ` Joel Fernandes
2023-08-24 13:28 ` Paul E. McKenney
2023-08-24 16:03 ` Huacai Chen
2023-08-24 16:32 ` Huacai Chen
2023-08-24 16:34 ` Paul E. McKenney
2023-08-24 2:47 ` Huacai Chen
2023-08-24 9:39 ` Thomas Gleixner
2023-08-24 13:21 ` Joel Fernandes
2023-08-24 13:29 ` Paul E. McKenney
2023-08-24 16:15 ` Huacai Chen
2023-08-23 21:36 ` 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=20230830010444.GA33437@google.com \
--to=joel@joelfernandes.org \
--cc=boqun.feng@gmail.com \
--cc=chenhuacai@kernel.org \
--cc=chenhuacai@loongson.cn \
--cc=frederic@kernel.org \
--cc=jiangshanlai@gmail.com \
--cc=josh@joshtriplett.org \
--cc=jstultz@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mingo@kernel.org \
--cc=paulmck@kernel.org \
--cc=qiang.zhang1211@gmail.com \
--cc=quic_neeraju@quicinc.com \
--cc=rcu@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=sboyd@kernel.org \
--cc=senozhatsky@chromium.org \
--cc=stable@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=zhoubinbin@loongson.cn \
/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