From: Tejun Heo <tj@kernel.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Jianchao Wang <jianchao.w.wang@oracle.com>,
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 09:30:32 -0700 [thread overview]
Message-ID: <20180911163032.GA2966370@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <20180911160532.GB10082@ming.t460p>
On Wed, Sep 12, 2018 at 12:05:33AM +0800, Ming Lei wrote:
> On Tue, Sep 11, 2018 at 08:49:59AM -0700, Tejun Heo wrote:
> > On Tue, Sep 11, 2018 at 11:45:41PM +0800, Ming Lei wrote:
> > > > So, this part seems wrong. The function is called percpu_ref_reinit()
> > > > - the refcnt is expected to be in its initial state with just the base
> > > > ref once this function returns. If you're removing the restriction on
> > >
> > > But the comment says that 'Re-initialize @ref so that it's in the same
> > > state as when it finished', and this invariant isn't changed with this
> > > patch.
> >
> > The comment goes "when perpcu_ref_init() finished". The function is
> > called re _init_. It should put the ref in the initial state, right?
>
> OK, I am fine to keep the behaviour for this API, will introduce a new helper
> for NVMe.
Why aren't switch_to_atomic/percpu enough?
> However, it is doable to switch to percpu mode from atomic mode when it
> doesn't drop to zero, looks like sort of perpcu_ref_reinit(inherit_old_refcount).
Isn't that way more contorted than just switching operating modes?
Thanks.
--
tejun
next prev parent reply other threads:[~2018-09-11 16:30 UTC|newest]
Thread overview: 30+ 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 8:20 ` Ming Lei
2018-09-11 14:22 ` jianchao.wang
2018-09-11 13:44 ` Tejun Heo
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 [this message]
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
2018-09-18 12:49 ` Tejun Heo
2018-09-19 2:51 ` Ming Lei
2018-09-19 20:36 ` Tejun Heo
2018-09-18 3:21 ` jianchao.wang
2018-09-18 7:34 ` Ming Lei
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