From: yuankuiz@codeaurora.org
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-pm@vger.kernel.org, rjw@rjwysocki.net, fweisbec@gmail.com,
peterz@infradead.org, aulmck@linux.vnet.ibm.com,
mingo@kernel.org, len.brown@intel.com,
linux-kernel@vger.kernel.org
Subject: Re: Subject: [PATCH] [PATCH] time: tick-sched: use bool for tick_stopped
Date: Tue, 10 Apr 2018 16:12:00 +0800 [thread overview]
Message-ID: <e1ef27ca497614463d4eb9a32eadfc00@codeaurora.org> (raw)
In-Reply-To: <alpine.DEB.2.21.1804100946060.2058@nanos.tec.linutronix.de>
On 2018-04-10 03:55 PM, Thomas Gleixner wrote:
> On Tue, 10 Apr 2018, yuankuiz@codeaurora.org wrote:
>
>> From: John Zhao <yuankuiz@codeaurora.org>
>>
>> Variable tick_stopped returned by tick_nohz_tick_stopped
>> can have only true / forse values. Since the return type
>> of the tick_nohz_tick_stopped is also bool, variable
>> tick_stopped nice to have data type as bool in place of int.
>
> The data type is not int.
[ZJ] Yes. Per newest tip in branch of linux-pm-cpuidle, it is unsigned
int with 1 bit in width.
There is typo in commit message, "int" at here should be "unsigned int"
> It's part of an integer bitfield and occupies
> exactly one bit of storage, while bool has an architecture dependend
> size
> and is at least 1 byte, i.e. 8 bit. So with alignment effects you grew
> the
> size of the data structure and therefore the cache foot print.
[ZJ] So, 1 bit in width is specified as:
+ bool tick_stopped : 1;
This patch is based on the linux-pm-cpuidle branch which has
already gathered available space in the structure of tick_sched.
>
> This is not about 'nice to have' ....
>
> Thanks,
>
> tglx
next prev parent reply other threads:[~2018-04-10 8:12 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-10 7:33 Subject: [PATCH] [PATCH] time: tick-sched: use bool for tick_stopped yuankuiz
2018-04-10 7:45 ` yuankuiz
2018-04-10 8:51 ` yuankuiz
2018-04-10 8:54 ` yuankuiz
2018-04-10 7:55 ` Subject: [PATCH] " Thomas Gleixner
2018-04-10 8:12 ` yuankuiz [this message]
2018-04-10 8:00 ` Rafael J. Wysocki
2018-04-10 8:15 ` yuankuiz
2018-04-10 9:10 ` Thomas Gleixner
2018-04-10 10:07 ` yuankuiz
2018-04-10 11:06 ` Thomas Gleixner
2018-04-10 14:08 ` yuankuiz
2018-04-10 14:49 ` yuankuiz
2018-04-10 23:09 ` yuankuiz
2018-04-10 23:20 ` yuankuiz
2018-04-20 1:47 ` yuankuiz
2018-04-20 6:44 ` yuankuiz
2018-04-20 19:24 ` Joe Perches
2018-04-25 7:01 ` yuankuiz
2018-04-10 11:26 ` Peter Zijlstra
2018-04-10 12:07 ` Thomas Gleixner
2018-04-10 12:26 ` Peter Zijlstra
2018-04-10 12:33 ` Subject: [PATCH] " Peter Zijlstra
2018-04-10 15:14 ` Joe Perches
2018-04-10 16:30 ` Peter Zijlstra
2018-04-10 15:41 ` [PATCH] checkpatch: whinge about bool bitfields Joe Perches
2018-04-10 18:19 ` [PATCH] checkpatch: Add a --strict test for structs with bool member definitions Joe Perches
2018-04-10 21:39 ` Andrew Morton
2018-04-10 21:53 ` Joe Perches
2018-04-10 22:00 ` Andrew Morton
2018-04-11 8:15 ` Peter Zijlstra
2018-04-11 16:29 ` Andrew Morton
2018-04-11 16:51 ` Joe Perches
2018-04-12 6:22 ` Julia Lawall
2018-04-12 6:42 ` Joe Perches
2018-04-12 7:03 ` Julia Lawall
2018-04-12 8:13 ` Peter Zijlstra
2018-04-14 21:19 ` Julia Lawall
2018-04-17 9:07 ` yuankuiz
2018-04-18 18:38 ` Joe Perches
2018-04-19 4:40 ` Julia Lawall
2018-04-19 4:51 ` Joe Perches
2018-04-19 5:16 ` Julia Lawall
2018-04-19 6:48 ` yuankuiz
2018-04-19 10:42 ` yuankuiz
2018-04-20 1:31 ` yuankuiz
2018-04-11 17:00 ` Peter Zijlstra
2018-04-12 7:47 ` Ingo Molnar
2018-04-12 8:11 ` Peter Zijlstra
2018-04-12 9:35 ` Andrea Parri
2018-04-12 11:50 ` Peter Zijlstra
2018-04-12 12:01 ` Joe Perches
2018-04-12 12:08 ` Peter Zijlstra
2018-04-12 12:38 ` Joe Perches
2018-04-12 16:47 ` Andrew Morton
2018-04-12 11:52 ` Kalle Valo
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