mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: Nikolay Borisov <nborisov@suse.com>
Cc: jbacik@fb.com, linux-kernel@vger.kernel.org, mgorman@techsingularity.net
Subject: Re: [PATCH v2 2/2] writeback: Rework wb_[dec|inc]_stat family of functions
Date: Tue, 20 Jun 2017 15:37:15 -0400	[thread overview]
Message-ID: <20170620193715.GF21326@htj.duckdns.org> (raw)
In-Reply-To: <1497981720-7036-1-git-send-email-nborisov@suse.com>

Hello, Nikolay.

On Tue, Jun 20, 2017 at 09:02:00PM +0300, Nikolay Borisov wrote:
> Currently the writeback statistics code uses a percpu counters to hold
> various statistics. Furthermore we have 2 families of functions - those which
> disable local irq and those which doesn't and whose names begin with
> double underscore. However, they both end up calling __add_wb_stats which in
> turn calls percpu_counter_add_batch which is already irq-safe.

Heh, looks like I was confused.  __percpu_counter_add() is not
irq-safe.  It disables preemption and uses __this_cpu_read(), so
there's no protection against irq.  If writeback statistics want
irq-safe operations and it does, it would need these separate
operations.  Am I missing something?

Thanks.

-- 
tejun

  reply	other threads:[~2017-06-20 19:37 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 [this message]
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 ` [PATCH 1/2] percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batch Tejun Heo
2017-06-20 18:01   ` [PATCH v2 " 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=20170620193715.GF21326@htj.duckdns.org \
    --to=tj@kernel.org \
    --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
all inboxes | Powered by JetHome®