From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: How to avoid spurious lockdep warnings?
Date: Fri, 21 Mar 2008 00:44:58 +0100 [thread overview]
Message-ID: <1206056698.6437.70.camel@lappy> (raw)
In-Reply-To: <47E2ECF3.2050606@goop.org>
On Thu, 2008-03-20 at 16:02 -0700, Jeremy Fitzhardinge wrote:
> In a Xen system, when a new pagetable is about to be put in use it is
> "pinned", meaning that each page in the pagetable is registered with the
> hypervisor. This is done in arch/x86/xen/mmu.c:pin_page().
>
> In order to make this efficient, the hypercalls for pinning are batched,
> so that multiple pages are submitted at once in a single multicall.
> While a page is batched pending the hypercall, its corresponding
> pte_lock is held.
>
> This means that the code can end up holding multiple pte locks at once,
> though it is guaranteed to never try to hold the same lock at once.
> However, because these locks are in the same lock class, I get a
> spurious warning from lockdep. Is there some way I can get rid of this
> warning?
How many locks at once?
next prev parent reply other threads:[~2008-03-20 23:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-20 23:02 How to avoid spurious lockdep warnings? Jeremy Fitzhardinge
2008-03-20 23:44 ` Peter Zijlstra [this message]
2008-03-21 5:35 ` Jeremy Fitzhardinge
2008-03-22 20:46 ` Arjan van de Ven
2008-03-22 21:08 ` Jeremy Fitzhardinge
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=1206056698.6437.70.camel@lappy \
--to=a.p.zijlstra@chello.nl \
--cc=jeremy@goop.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
/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