From: "Jan Beulich" <JBeulich@novell.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Steven Smith <Steven.Smith@eu.citrix.com>,
Ian Pratt <Ian.Pratt@eu.citrix.com>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Dongxiao Xu <dongxiao.xu@intel.com>
Subject: Re: [Pv-ops][PATCH] Netback multiple tasklet support
Date: Wed, 13 Jan 2010 10:17:18 +0000 [thread overview]
Message-ID: <4B4DABBE0200007800029A6F@vpn.id2.novell.com> (raw)
In-Reply-To: <1260436078.23698.45463.camel@zakaz.uk.xensource.com>
>>> Ian Campbell <Ian.Campbell@citrix.com> 10.12.09 10:07 >>>
>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.
Wouldn't safe-against-softirq be sufficient then? Or if not (i.e. if meant
to be generic), wouldn't the irq-safe variant need to be used
independent of the new feature (and then also in the 2.6.18 tree)?
Jan
next prev parent reply other threads:[~2010-01-13 10:17 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
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 ` Jan Beulich [this message]
2010-01-14 16:55 ` [Pv-ops][PATCH] Netback multiple tasklet support Ian Campbell
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=4B4DABBE0200007800029A6F@vpn.id2.novell.com \
--to=jbeulich@novell.com \
--cc=Ian.Campbell@citrix.com \
--cc=Ian.Pratt@eu.citrix.com \
--cc=Steven.Smith@eu.citrix.com \
--cc=dongxiao.xu@intel.com \
--cc=jeremy@goop.org \
--cc=xen-devel@lists.xensource.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).