From: Keir Fraser <keir@xen.org>
To: Jean Guyader <jean.guyader@eu.citrix.com>, xen-devel@lists.xensource.com
Cc: tim@xen.org, allen.m.kay@intel.com
Subject: Re: [PATCH 4/6] mm: Add new map space for add_to_physmap, XENMAPSPACE_gmfn_range.
Date: Fri, 04 Nov 2011 14:47:53 +0000 [thread overview]
Message-ID: <CAD9AB99.33980%keir@xen.org> (raw)
In-Reply-To: <1320403109-8739-5-git-send-email-jean.guyader@eu.citrix.com>
On 04/11/2011 10:38, "Jean Guyader" <jean.guyader@eu.citrix.com> wrote:
>
> XENMAPSPACE_gmfn_range is like XENMAPSPACE_gmfn but with a size which
> is the number of pages on which xen will iterate.
You can't really extend the size of an existing ABI structure, and always
copy that extended size. Older guests won't know to guarantee that the
extended space is accessible. I suggest you make your new field a uint16_t,
placed directly after the domid field. Then you are making use of existing
pad space. 64k pages = 256MB at a time should be plenty of amortisation.
And, even with the reduced field width, I could imagine 64k remappings
taking a good while. The remapping loop should regularly (even every
iteration) check hypercall_preempt_check(), then
hypercall_create_continuation() and exit if the hypercall is being requested
to voluntarily yield.
-- Keir
> Signed-off-by: Jean Guyader <jean.guyader@eu.citrix.com>
> ---
> xen/arch/x86/mm.c | 15 ++++++++++++++-
> xen/include/public/memory.h | 4 ++++
> 2 files changed, 18 insertions(+), 1 deletions(-)
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
prev parent reply other threads:[~2011-11-04 14:47 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-04 10:38 [PATCH 0/6] IOMMU, vtd and iotlb flush rework Jean Guyader
2011-11-04 10:38 ` [PATCH 1/6] vtd: Refactor iotlb flush code Jean Guyader
2011-11-04 10:38 ` [PATCH 2/6] iommu: Introduce iommu_flush and iommu_flush_all Jean Guyader
2011-11-04 10:38 ` [PATCH 3/6] add_to_physmap: Move the code for XENMEM_add_to_physmap Jean Guyader
2011-11-04 10:38 ` [PATCH 4/6] mm: Add new map space for add_to_physmap, XENMAPSPACE_gmfn_range Jean Guyader
2011-11-04 10:38 ` [PATCH 5/6] hvmloader: Change memory relocation loop when overlap with PCI hole Jean Guyader
2011-11-04 10:38 ` [PATCH 6/6] Introduce domain flag (dont_flush_iotlb) to avoid unnecessary iotlb flush Jean Guyader
2011-11-04 12:41 ` Jan Beulich
2011-11-04 14:52 ` [PATCH 5/6] hvmloader: Change memory relocation loop when overlap with PCI hole Keir Fraser
2011-11-04 12:32 ` [PATCH 4/6] mm: Add new map space for add_to_physmap, XENMAPSPACE_gmfn_range Jan Beulich
2011-11-04 14:47 ` Keir Fraser [this message]
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