All of lore.kernel.org
 help / color / mirror / Atom feed
From: Tejun Heo <tj@kernel.org>
To: "jianchao.wang" <jianchao.w.wang@oracle.com>
Cc: Ming Lei <ming.lei@redhat.com>,
	linux-kernel@vger.kernel.org,
	Kent Overstreet <kent.overstreet@gmail.com>,
	linux-block@vger.kernel.org
Subject: Re: [PATCH] percpu-refcount: relax limit on percpu_ref_reinit()
Date: Tue, 11 Sep 2018 06:44:04 -0700	[thread overview]
Message-ID: <20180911134404.GF1100574@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <771fa1eb-85d3-2ff2-6070-207874da85b6@oracle.com>

Hello,

On Tue, Sep 11, 2018 at 12:40:36PM +0800, jianchao.wang wrote:
> (long)(sum (every cpu's refcounter)) + atomic refcounter
> 
> and when switch to atomic mode, there could be value left in atomic refcounter.
> then the unsigned long percpu refcounter cound be decreased from 0.

It can always do that.  Imagine a task getting a ref on one cpu,
migrating and putting it on another.  The only thing which matters is
that the sum of everything adds upto what it should be.

Thanks.

-- 
tejun

  parent reply	other threads:[~2018-09-11 18:43 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-09 12:58 [PATCH] percpu-refcount: relax limit on percpu_ref_reinit() Ming Lei
2018-09-09 18:46 ` Bart Van Assche
2018-09-09 23:59   ` Ming Lei
2018-09-10  1:40 ` jianchao.wang
2018-09-10 16:11   ` Ming Lei
2018-09-11  1:48     ` jianchao.wang
2018-09-11  4:03       ` Ming Lei
2018-09-11  4:40         ` jianchao.wang
2018-09-11  4:40           ` jianchao.wang
2018-09-11  8:20           ` Ming Lei
2018-09-11 14:22             ` jianchao.wang
2018-09-11 13:44           ` Tejun Heo [this message]
2018-09-11 14:13             ` jianchao.wang
2018-09-10  1:54 ` jianchao.wang
2018-09-10 16:49 ` Tejun Heo
2018-09-11  0:00   ` Ming Lei
2018-09-11 13:48     ` Tejun Heo
2018-09-11 15:45       ` Ming Lei
2018-09-11 15:49         ` Tejun Heo
2018-09-11 16:05           ` Ming Lei
2018-09-11 16:30             ` Tejun Heo
2018-09-11 16:34               ` Ming Lei
2018-09-11 16:38                 ` Tejun Heo
2018-09-12  1:52                   ` Ming Lei
2018-09-12 15:53                     ` Tejun Heo
2018-09-12 22:11                       ` Ming Lei
2018-09-12 22:11                         ` Ming Lei
2018-09-18 12:49                         ` Tejun Heo
2018-09-18 12:49                           ` Tejun Heo
2018-09-19  2:51                           ` Ming Lei
2018-09-19  2:51                             ` Ming Lei
2018-09-19 20:36                             ` Tejun Heo
2018-09-19 20:36                               ` Tejun Heo
2018-09-18  3:21 ` jianchao.wang
2018-09-18  7:34   ` Ming Lei

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=20180911134404.GF1100574@devbig004.ftw2.facebook.com \
    --to=tj@kernel.org \
    --cc=jianchao.w.wang@oracle.com \
    --cc=kent.overstreet@gmail.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=ming.lei@redhat.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 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.