From: Tejun Heo <tj@kernel.org>
To: Nikolay Borisov <nborisov@suse.com>
Cc: jbacik@fb.com, jack@suse.cz, linux-kernel@vger.kernel.org,
hannes@cmpxchg.org, mgorman@techsingularity.net
Subject: Re: [PATCH 1/2] percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch
Date: Tue, 20 Jun 2017 13:28:35 -0400 [thread overview]
Message-ID: <20170620172835.GA21326@htj.duckdns.org> (raw)
In-Reply-To: <1497958590-6639-1-git-send-email-nborisov@suse.com>
Hello, Nikolay.
On Tue, Jun 20, 2017 at 02:36:29PM +0300, Nikolay Borisov wrote:
> 252e0ba6b77d ("lib: percpu_counter variable batch") added a batched version
> of percpu_counter_add. However, one problem with this patch is the fact that it
> overloads the meaning of double underscore, which in kernel-land are taken
> to implicitly mean there is no preempt protection for the API. Currently, in
I don't think the above holds. We use __ for quite a few different
things. Sometimes it denotes internal functions which shouldn't be
used outside a subsystem, sometimes just more explicit / verbose
versions of certain operations, at other times less protection against
preemption / irq / whatever.
> both !SMP and SMP configs percpu_counter_add calls __percpu_counter_add which
> is preempt safe due to explicit calls to preempt_disable. This state of play
> creates the false sense that __percpu_counter_add is less SMP-safe than
> percpu_counter_add. They are both identical irrespective of CONFIG_SNMP value.
> The only difference is that the __ version takes a batch parameter.
>
> Make this a bit more explicit by just renaming __percpu_counter_add to
> percpu_counter_add_batch.
I'm all for making the function name more explicit, but can you please
drop the first part of the commit description?
Thanks.
--
tejun
next prev parent reply other threads:[~2017-06-20 17:28 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-20 11:36 [PATCH 1/2] percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch Nikolay Borisov
2017-06-20 11:36 ` [PATCH 2/2] writeback: Rework wb_[dec|inc]_stat family of functions Nikolay Borisov
2017-06-20 17:33 ` Tejun Heo
2017-06-20 18:02 ` [PATCH v2 " Nikolay Borisov
2017-06-20 19:37 ` Tejun Heo
2017-06-20 20:28 ` Nikolay Borisov
2017-06-20 20:30 ` Tejun Heo
2017-06-20 20:32 ` Nikolay Borisov
2017-06-21 7:25 ` [PATCH v3] " Nikolay Borisov
2017-06-21 15:59 ` Tejun Heo
2017-06-22 8:38 ` Jan Kara
2017-06-21 0:05 ` [PATCH 2/2] " kbuild test robot
2017-06-20 17:28 ` Tejun Heo [this message]
2017-06-20 18:01 ` [PATCH v2 1/2] percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch Nikolay Borisov
2017-06-20 19:47 ` [PATCH] " Tejun Heo
2017-06-20 19:55 ` David Miller
2017-06-21 1:14 ` Darrick J. Wong
2017-06-21 12:08 ` David Sterba
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=20170620172835.GA21326@htj.duckdns.org \
--to=tj@kernel.org \
--cc=hannes@cmpxchg.org \
--cc=jack@suse.cz \
--cc=jbacik@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mgorman@techsingularity.net \
--cc=nborisov@suse.com \
/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;
as well as URLs for NNTP newsgroup(s).