From: Lars-Peter Clausen <lars@metafoo.de>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>,
devel@driverdev.osuosl.org, linux-iio@vger.kernel.org,
Jonathan Cameron <jic23@kernel.org>
Subject: Re: [PATCH v2 5/6] staging:iio:events: Use non-atomic bitops
Date: Thu, 02 Feb 2012 10:14:25 +0100 [thread overview]
Message-ID: <4F2A53F1.3020304@metafoo.de> (raw)
In-Reply-To: <20120202062053.GC24652@mwanda>
On 02/02/2012 07:20 AM, Dan Carpenter wrote:
> On Wed, Feb 01, 2012 at 07:45:55PM +0100, Lars-Peter Clausen wrote:
>> We always hold the waitqueue lock when modifying the flags field. So it is safe
>> to use the non-atomic bitops here instead of the atomic versions.
>>
>> The lock has to be held, because we need to clear the busy flag and flush the
>> event fifo in one atomic operation when closing the event file descriptor.
>>
>
> Is the performance improvement worth it?
>
I don't think there is any real performance improvement to be expected of
this patch. If you have good a reason why non-atomic bitops should not be
used I guess this patch could be dropped. But right now I don't see anything
wrong with it.
Thanks,
- Lars
next prev parent reply other threads:[~2012-02-02 9:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-01 18:45 [PATCH v2 0/6] staging:iio: Event handling updates Lars-Peter Clausen
2012-02-01 18:45 ` [PATCH v2 1/6] staging:iio: Update iio_event_interface documentation Lars-Peter Clausen
2012-02-01 18:45 ` [PATCH v2 2/6] staging:iio: Factor out event handling into its own file Lars-Peter Clausen
2012-02-01 18:45 ` [PATCH v2 3/6] staging:iio:events: Use kfifo for event queue Lars-Peter Clausen
2012-02-01 18:45 ` [PATCH v2 4/6] staging:iio:events: Use waitqueue lock to protect " Lars-Peter Clausen
2012-02-01 18:45 ` [PATCH v2 5/6] staging:iio:events: Use non-atomic bitops Lars-Peter Clausen
2012-02-02 6:20 ` Dan Carpenter
2012-02-02 9:14 ` Lars-Peter Clausen [this message]
2012-02-02 11:19 ` Dan Carpenter
2012-02-02 11:49 ` Dan Carpenter
2012-02-02 14:15 ` J.I. Cameron
2012-02-01 18:45 ` [PATCH v2 6/6] staging:iio:events: Add poll support Lars-Peter Clausen
2012-02-01 19:49 ` [PATCH v2 0/6] staging:iio: Event handling updates Lars-Peter Clausen
2012-02-01 23:21 ` Greg KH
-- strict thread matches above, loose matches on Subject: below --
2012-02-01 21:17 Lars-Peter Clausen
2012-02-01 21:17 ` [PATCH v2 5/6] staging:iio:events: Use non-atomic bitops Lars-Peter Clausen
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=4F2A53F1.3020304@metafoo.de \
--to=lars@metafoo.de \
--cc=dan.carpenter@oracle.com \
--cc=devel@driverdev.osuosl.org \
--cc=gregkh@suse.de \
--cc=jic23@kernel.org \
--cc=linux-iio@vger.kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.