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xen/privcmd: improve performance of MMAPBATCH_V2

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Make the IOCTL_PRIVCMD_MMAPBATCH_V2 (and older V1 version) map
multiple frames at a time rather than one at a time, despite the pages
being non-consecutive GFNs.

xen_remap_foreign_mfn_array() is added which maps an array of GFNs
(instead of a consecutive range of GFNs).

Since per-frame errors are returned in an array, privcmd must set the
MMAPBATCH_V1 error bits as part of the "report errors" phase, after
all the frames are mapped.

Migrate times are significantly improved (when using a PV toolstack
domain).  For example, for an idle 12 GiB PV guest:

        Before     After
  real  0m38.179s  0m26.868s
  user  0m15.096s  0m13.652s
  sys   0m28.988s  0m18.732s

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
This commit is contained in:
David Vrabel
2015-03-11 14:49:57 +00:00
parent 628c28eefd
commit 4e8c0c8c4b
5 changed files with 249 additions and 80 deletions
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45
include/xen/xen-ops.h
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@@ -27,17 +27,54 @@ int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order);
struct vm_area_struct;
/*
* xen_remap_domain_mfn_array() - map an array of foreign frames
* @vma: VMA to map the pages into
* @addr: Address at which to map the pages
* @gfn: Array of GFNs to map
* @nr: Number entries in the GFN array
* @err_ptr: Returns per-GFN error status.
* @prot: page protection mask
* @domid: Domain owning the pages
* @pages: Array of pages if this domain has an auto-translated physmap
*
* @gfn and @err_ptr may point to the same buffer, the GFNs will be
* overwritten by the error codes after they are mapped.
*
* Returns the number of successfully mapped frames, or a -ve error
* code.
*/
int xen_remap_domain_mfn_array(struct vm_area_struct *vma,
unsigned long addr,
xen_pfn_t *gfn, int nr,
int *err_ptr, pgprot_t prot,
unsigned domid,
struct page **pages);
/* xen_remap_domain_mfn_range() - map a range of foreign frames
* @vma: VMA to map the pages into
* @addr: Address at which to map the pages
* @gfn: First GFN to map.
* @nr: Number frames to map
* @prot: page protection mask
* @domid: Domain owning the pages
* @pages: Array of pages if this domain has an auto-translated physmap
*
* Returns the number of successfully mapped frames, or a -ve error
* code.
*/
int xen_remap_domain_mfn_range(struct vm_area_struct *vma,
unsigned long addr,
xen_pfn_t mfn, int nr,
xen_pfn_t gfn, int nr,
pgprot_t prot, unsigned domid,
struct page **pages);
int xen_unmap_domain_mfn_range(struct vm_area_struct *vma,
int numpgs, struct page **pages);
int xen_xlate_remap_gfn_range(struct vm_area_struct *vma,
int xen_xlate_remap_gfn_array(struct vm_area_struct *vma,
unsigned long addr,
xen_pfn_t gfn, int nr,
pgprot_t prot,
xen_pfn_t *gfn, int nr,
int *err_ptr, pgprot_t prot,
unsigned domid,
struct page **pages);
int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,