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From: Andres Lagar Cavilla <andres@lagarcavilla.org>
To: Jan Beulich <JBeulich@suse.com>
Cc: "Wangyufei (James)" <james.wangyufei@huawei.com>,
	"Zhangbo (Oscar)" <oscar.zhangbo@huawei.com>,
	"Huangpeng (Peter)" <peter.huangpeng@huawei.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	Linqiangmin <linqiangmin@huawei.com>,
	"Herongguang (Stephen)" <herongguang.he@huawei.com>
Subject: Re: gfn_lock() seems useless.
Date: Tue, 2 Feb 2016 20:55:50 -0800	[thread overview]
Message-ID: <CADzFZPtJgb9nB+cKh+Jb6AMG51YPsY32hYSyVuwU4XV3Ue_k5w@mail.gmail.com> (raw)
In-Reply-To: <56B0E6CD02000078000CDA09@prv-mh.provo.novell.com>


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At the time, I had a patch queue for splitting the p2m locking into a tree
of per-2M locks. Very similar to Linux's split locks. I scaffolded the
macros to allow for that expansion. Then, I got pulled onto other things.

Andres

On Tue, Feb 2, 2016 at 8:26 AM, Jan Beulich <JBeulich@suse.com> wrote:

> >>> On 02.02.16 at 07:54, <oscar.zhangbo@huawei.com> wrote:
> > Hi all:
> > In patch e1e40bccee7490a01ac7d1f759ec2bbafd3c7185, it says that"many
> > routines can logically assert holding the p2m *FOR A SPECIFIC GFN.*" ,
> > But I find out that it did nothing for locking a single gfn, in fact  it
> > still locked the entire p2m list.
> >
> > -#define p2m_lock_recursive(p) mm_lock_recursive(p2m, &(p)->lock)
> > +#define gfn_lock(p,g,o)       mm_lock_recursive(p2m, &(p)->lock)  //'g'
> is not
> > used. The entire p2m list is locked.
> >
> >
> > Do we have any plan to lock a specific gfn?
>
> This indeed is a long term plan, but afaik no-one is currently
> doing any work in that direction.
>
> Jan
>
>

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  reply	other threads:[~2016-02-03  4:55 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-02  6:54 gfn_lock() seems useless Zhangbo (Oscar)
2016-02-02 16:26 ` Jan Beulich
2016-02-03  4:55   ` Andres Lagar Cavilla [this message]
2016-02-03 15:01     ` Konrad Rzeszutek Wilk

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