From: David Vrabel <david.vrabel@citrix.com>
To: <hansechang@gmail.com>, <linux-kernel@vger.kernel.org>,
<xen-devel@lists.xen.org>
Cc: Chang Huaixin <huaixin.chx@alibaba-inc.com>,
<jinsong.liu@alibaba-inc.com>, <Ian.Campbell@eu.citrix.com>,
<david.vrabel@citrix.com>, <dgdegra@tycho.nsa.gov>,
<boris.ostrovsky@oracle.com>
Subject: Re: [Xen-devel] [PATCH] Input: xen-kbdfront - free grant table entry in xenkbd_disconnect_backend
Date: Thu, 16 Oct 2014 17:01:09 +0100 [thread overview]
Message-ID: <543FEBC5.2050202@citrix.com> (raw)
In-Reply-To: <1413423992-3005-1-git-send-email-hansechang@gmail.com>
On 16/10/14 02:46, hansechang@gmail.com wrote:
> From: Chang Huaixin <huaixin.chx@alibaba-inc.com>
>
> xenkbd_disconnect_backend doesn't free grant table entry.
> This bug affects live migration.
>
> xenkbd_disconnect_backend uses gnttab_end_foreign_access_ref
> to handle grant table entry which doesn't really free an entry.
>
> Thus every time we do xenkbd_resume, grant table entry increses
> by one. As an grant table entry occupies 8 bytes, an grant table
> page has at most 512 entries. Every 512 times we do xenkdb_resume,
> grant table pages increses by one.
>
> After around 3500 times of live migration, grant table pages
> will increase by 7, causing too many pages to populate and hitting
> max_pages limit when assigning pages.Thus assign_pages will fail,
> so will live migration.
Acked-by: David Vrabel <david.vrabel@citrix.com>
This need to be send to the input subsystem maintainers.
David
next prev parent reply other threads:[~2014-10-16 16:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-16 1:46 [PATCH] Input: xen-kbdfront - free grant table entry in xenkbd_disconnect_backend hansechang
2014-10-16 16:01 ` David Vrabel
2014-10-16 16:01 ` David Vrabel [this message]
2014-10-16 20:37 ` Dmitry Torokhov
2014-10-16 20:37 ` [Xen-devel] " Dmitry Torokhov
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