From: Pavel Skripkin <paskripkin@gmail.com>
To: David Laight <David.Laight@ACULAB.COM>,
Michael Straube <straube.linux@gmail.com>,
"Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
Larry Finger <Larry.Finger@lwfinger.net>,
Phillip Potter <phil@philpotter.co.uk>,
"open list:STAGING SUBSYSTEM" <linux-staging@lists.linux.dev>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: staging: r8188eu: how to handle nested mutex under spinlock
Date: Mon, 4 Apr 2022 19:38:55 +0300 [thread overview]
Message-ID: <3c8b6454-6b52-fe62-8db1-c76bdbeb2df0@gmail.com> (raw)
In-Reply-To: <4ef1e90716e64fd78ebbc222bbb7e597@AcuMS.aculab.com>
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Hi David,
On 4/4/22 11:50, David Laight wrote:
>>
>> > while (pwrpriv->bInSuspend &&
>>
>> I've looked into what gcc11 produced from this function and looks like
>> my compiler is smart enough to not cache that value, but I am afraid not
>> all compilers are that smart.
>
> The compiler can't cache the value because of the function call.
>
Hm, I am a newbie in compilers, so can you, please, explain (or give a
link to any resource where I can read about it) how function call here
prevent caching.
IIUC compiler generates code that works well in scope of single-threaded
application, so why can't compiler cache that value instead of accessing
memory on each iteration... Isn't register access a way faster than even
cache hit?
Thanks!
With regards,
Pavel Skripkin
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next prev parent reply other threads:[~2022-04-04 21:23 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-02 20:47 staging: r8188eu: how to handle nested mutex under spinlock Michael Straube
2022-04-02 21:13 ` Pavel Skripkin
2022-04-02 21:32 ` Larry Finger
2022-04-03 8:44 ` Michael Straube
[not found] ` <4389354.LvFx2qVVIh@leap>
[not found] ` <1813843.tdWV9SEqCh@leap>
2022-04-03 11:08 ` Michael Straube
[not found] ` <7365301.EvYhyI6sBW@leap>
2022-04-03 11:41 ` Michael Straube
2022-04-03 11:48 ` Pavel Skripkin
[not found] ` <1817830.CQOukoFCf9@leap>
2022-04-03 12:14 ` Michael Straube
2022-04-03 12:19 ` Pavel Skripkin
[not found] ` <4412825.cEBGB3zze1@leap>
2022-04-03 12:45 ` Pavel Skripkin
[not found] ` <2029549.KlZ2vcFHjT@leap>
2022-04-03 13:02 ` Pavel Skripkin
2022-04-03 20:51 ` Michael Straube
2022-04-03 21:15 ` Pavel Skripkin
2022-04-04 8:50 ` David Laight
2022-04-04 16:38 ` Pavel Skripkin [this message]
2022-04-04 16:59 ` David Laight
2022-04-04 17:12 ` Pavel Skripkin
[not found] ` <1858641.taCxCBeP46@leap>
[not found] ` <2366209.jE0xQCEvom@leap>
2022-04-03 12:18 ` Michael Straube
2022-04-04 13:33 ` Dan Carpenter
2022-04-04 14:16 ` Michael Straube
[not found] ` <3097543.5fSG56mABF@leap>
2022-04-03 11:44 ` Michael Straube
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