From: Greg KH <gregkh@linuxfoundation.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: outreachy-kernel@googlegroups.com,
Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
Subject: Re: [Outreachy kernel] [PATCH] Staging: comedi: Use rwsemaphore
Date: Thu, 29 Oct 2015 15:33:55 -0700 [thread overview]
Message-ID: <20151029223355.GA19648@kroah.com> (raw)
In-Reply-To: <5132136.EW41hst8xX@wuerfel>
On Thu, Oct 29, 2015 at 11:20:46PM +0100, Arnd Bergmann wrote:
> On Wednesday 28 October 2015 13:46:25 Greg KH wrote:
> > On Tue, Oct 27, 2015 at 09:23:16PM -0700, Ksenija Stanojevic wrote:
> > > Functions that use semaphore for locking are divided into read/write
> > > functions, so use locking mechanism that provides similar semantics.
> > >
> > > Signed-off-by: Ksenija Stanojevic <ksenija.stanojevic@gmail.com>
> >
> > Unless you can measure the speed differences by switching to such a
> > lock, never switch to such a lock as they are much more complex and can
> > actually cause things to go _slower_.
> >
> > So I can't take this patch unless you have measureable benchmark
> > numbers.
> >
>
> Agreed. However, changing this driver to use 'struct mutex' would
> be an obvious improvement and should be safe as far as I can tell.
Yes, that's fine to do.
greg k-h
prev parent reply other threads:[~2015-10-29 22:34 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-28 4:23 [PATCH] Staging: comedi: Use rwsemaphore Ksenija Stanojevic
2015-10-28 4:46 ` [Outreachy kernel] " Greg KH
2015-10-29 22:20 ` Arnd Bergmann
2015-10-29 22:33 ` Greg KH [this message]
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