From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Steven Smith <Steven.Smith@eu.citrix.com>,
"Xu, Dongxiao" <dongxiao.xu@intel.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Ian Pratt <Ian.Pratt@eu.citrix.com>
Subject: Re: [Pv-ops][PATCH] Netback multiple tasklet support
Date: Thu, 10 Dec 2009 09:54:20 -0800 [thread overview]
Message-ID: <4B2135CC.6000004@goop.org> (raw)
In-Reply-To: <1260436078.23698.45463.camel@zakaz.uk.xensource.com>
On 12/10/09 01:07, Ian Campbell wrote:
> Subject: xen: ensure locking gnttab_copy_grant_page is safe against interrupts.
>
> Now that netback processing occurs in a thread instead of a tasklet
> gnttab_copy_grant_page needs to be safe against interrupts.
>
> The code is currently commented out in this tree but on 2.6.18 we observed a
> deadlock where the netback thread called gnttab_copy_grant_page, locked
> gnttab_dma_lock for writing, was interrupted and on return from interrupt the
> network stack's TX tasklet ended up calling __gnttab_dma_map_page via the
> hardware driver->swiotlb and tries to take gnttab_dma_lock for reading.
>
> Correct the commented code so we don't get bitten if/when it is re-enabled.
>
What's the issue here? I'm inclined to just remove the commented-out
code if it isn't being used, and re-evaluate the locking if/when it
becomes necessary.
J
next prev parent reply other threads:[~2009-12-10 17:54 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-27 2:26 [Pv-ops][PATCH] Netback multiple tasklet support Xu, Dongxiao
2009-11-27 9:42 ` Ian Campbell
2009-11-27 16:08 ` Xu, Dongxiao
2009-11-27 16:15 ` Ian Pratt
2009-11-27 16:57 ` Xu, Dongxiao
2009-11-28 13:15 ` Ian Pratt
2009-12-02 10:17 ` Xu, Dongxiao
2009-12-03 21:28 ` Jeremy Fitzhardinge
2009-12-04 2:13 ` Xu, Dongxiao
2009-12-04 2:33 ` Jeremy Fitzhardinge
2009-12-08 9:22 ` Xu, Dongxiao
2009-12-09 20:23 ` Jeremy Fitzhardinge
2009-12-10 3:29 ` Xu, Dongxiao
2009-12-10 18:01 ` Jeremy Fitzhardinge
2009-12-11 1:34 ` Xu, Dongxiao
2010-04-26 14:27 ` [Pv-ops][PATCH 0/3] Resend: Netback multiple thread support Xu, Dongxiao
2010-04-27 0:19 ` Konrad Rzeszutek Wilk
2010-04-27 0:40 ` Xu, Dongxiao
2010-04-27 3:02 ` Xu, Dongxiao
2010-04-27 10:49 ` Steven Smith
2010-04-27 18:37 ` Jeremy Fitzhardinge
2010-04-28 9:31 ` Steven Smith
2010-04-28 11:36 ` Xu, Dongxiao
2010-04-28 12:04 ` Steven Smith
2010-04-28 13:33 ` Xu, Dongxiao
2010-04-30 7:35 ` Steven Smith
2010-04-28 10:27 ` Xu, Dongxiao
2010-04-28 11:51 ` Steven Smith
2010-04-28 12:23 ` Xu, Dongxiao
2010-04-28 12:43 ` Jan Beulich
2010-04-30 7:29 ` Steven Smith
2010-04-30 8:27 ` Jan Beulich
2009-12-10 9:07 ` [Pv-ops][PATCH] Netback multiple tasklet support Ian Campbell
2009-12-10 17:54 ` Jeremy Fitzhardinge [this message]
2009-12-10 18:07 ` Ian Campbell
2009-12-11 8:34 ` Jan Beulich
2009-12-11 9:34 ` Ian Campbell
2009-12-11 14:24 ` Konrad Rzeszutek Wilk
2010-03-17 8:46 ` [PATCH] [pv-ops] fix dom0 S3 when MSI is used Cui, Dexuan
2010-03-17 14:28 ` Konrad Rzeszutek Wilk
2010-03-18 3:05 ` Cui, Dexuan
2010-03-19 1:04 ` Jeremy Fitzhardinge
2010-03-19 1:03 ` Jeremy Fitzhardinge
2010-03-19 1:29 ` Cui, Dexuan
2010-01-13 10:17 ` [Pv-ops][PATCH] Netback multiple tasklet support Jan Beulich
2010-01-14 16:55 ` Ian Campbell
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