From: Tim Deegan <tim@xen.org>
To: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Cc: george.dunlap@eu.citrix.com, andres@gridcentric.ca,
xen-devel@lists.xensource.com, keir.xen@gmail.com,
adin@gridcentric.ca
Subject: Re: [PATCH 1 of 7] Make p2m lookups fully synchronized wrt modifications
Date: Fri, 10 Feb 2012 15:33:59 +0000 [thread overview]
Message-ID: <20120210153359.GA32107@ocelot.phlegethon.org> (raw)
In-Reply-To: <e29c2634afb1de9aee84.1328766346@xdev.gridcentric.ca>
At 00:45 -0500 on 09 Feb (1328748346), Andres Lagar-Cavilla wrote:
> We achieve this by locking/unlocking the global p2m_lock in get/put_gfn.
>
> The lock is always taken recursively, as there are many paths that
> call get_gfn, and later, make another attempt at grabbing the p2m_lock.
>
> The lock is not taken for shadow lookups. We believe there are no problems
> remaining for synchronized p2m+shadow paging, but we are not enabling this
> combination due to lack of testing. Unlocked shadow p2m access are tolerable as
> long as shadows do not gain support for paging or sharing.
>
> HAP (EPT) lookups and all modifications do take the lock.
>
> Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Acked-by: Tim Deegan <tim@xen.org>
next prev parent reply other threads:[~2012-02-10 15:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-09 5:45 [PATCH 0 of 7] Synchronized p2m lookups v2 Andres Lagar-Cavilla
2012-02-09 5:45 ` [PATCH 1 of 7] Make p2m lookups fully synchronized wrt modifications Andres Lagar-Cavilla
2012-02-10 15:33 ` Tim Deegan [this message]
2012-02-09 5:45 ` [PATCH 2 of 7] Clean up locking now that p2m lockups are fully synchronized Andres Lagar-Cavilla
2012-02-09 5:45 ` [PATCH 3 of 7] Rework locking in the PoD layer Andres Lagar-Cavilla
2012-02-09 12:07 ` George Dunlap
2012-02-09 14:45 ` Andres Lagar-Cavilla
2012-02-10 15:36 ` Tim Deegan
2012-02-10 15:43 ` Tim Deegan
2012-02-10 15:47 ` Andres Lagar-Cavilla
2012-02-10 15:59 ` George Dunlap
2012-02-09 5:45 ` [PATCH 4 of 7] Re-order calls to put_gfn() around wait queue invocations Andres Lagar-Cavilla
2012-02-09 5:45 ` [PATCH 5 of 7] x86/mm: Revert changeset 24582:f6c33cfe7333 Andres Lagar-Cavilla
2012-02-09 5:45 ` [PATCH 6 of 7] x86/mm: Refactor possibly deadlocking get_gfn calls Andres Lagar-Cavilla
2012-02-09 5:45 ` [PATCH 7 of 7] x86/mm: When removing/adding a page from/to the physmap, keep in mind it could be shared Andres Lagar-Cavilla
2012-02-10 15:38 ` Tim Deegan
2012-02-10 16:10 ` [PATCH 0 of 7] Synchronized p2m lookups v2 Tim Deegan
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