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authorDavid Vrabel <david.vrabel@citrix.com>2015-03-11 15:49:57 +0100
committerDavid Vrabel <david.vrabel@citrix.com>2015-03-16 15:49:15 +0100
commit4e8c0c8c4bf3a5b5c98046e146ab3884bf7a7d0e (patch)
treee2da5980fd405c7109a342b13f0a2a1214f94b61 /drivers/xen/xlate_mmu.c
parentxen: unify foreign GFN map/unmap for auto-xlated physmap guests (diff)
downloadlinux-4e8c0c8c4bf3a5b5c98046e146ab3884bf7a7d0e.tar.xz
linux-4e8c0c8c4bf3a5b5c98046e146ab3884bf7a7d0e.zip
xen/privcmd: improve performance of MMAPBATCH_V2
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>
Diffstat (limited to 'drivers/xen/xlate_mmu.c')
-rw-r--r--drivers/xen/xlate_mmu.c46
1 files changed, 28 insertions, 18 deletions
diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c
index 7724d90fc697..58a5389aec89 100644
--- a/drivers/xen/xlate_mmu.c
+++ b/drivers/xen/xlate_mmu.c
@@ -62,13 +62,15 @@ static int map_foreign_page(unsigned long lpfn, unsigned long fgmfn,
}
struct remap_data {
- xen_pfn_t fgmfn; /* foreign domain's gmfn */
+ xen_pfn_t *fgmfn; /* foreign domain's gmfn */
pgprot_t prot;
domid_t domid;
struct vm_area_struct *vma;
int index;
struct page **pages;
struct xen_remap_mfn_info *info;
+ int *err_ptr;
+ int mapped;
};
static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
@@ -80,38 +82,46 @@ static int remap_pte_fn(pte_t *ptep, pgtable_t token, unsigned long addr,
pte_t pte = pte_mkspecial(pfn_pte(pfn, info->prot));
int rc;
- rc = map_foreign_page(pfn, info->fgmfn, info->domid);
- if (rc < 0)
- return rc;
- set_pte_at(info->vma->vm_mm, addr, ptep, pte);
+ rc = map_foreign_page(pfn, *info->fgmfn, info->domid);
+ *info->err_ptr++ = rc;
+ if (!rc) {
+ set_pte_at(info->vma->vm_mm, addr, ptep, pte);
+ info->mapped++;
+ }
+ info->fgmfn++;
return 0;
}
-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, unsigned domid,
+ xen_pfn_t *mfn, int nr,
+ int *err_ptr, pgprot_t prot,
+ unsigned domid,
struct page **pages)
{
int err;
struct remap_data data;
+ unsigned long range = nr << PAGE_SHIFT;
- /* TBD: Batching, current sole caller only does page at a time */
- if (nr > 1)
- return -EINVAL;
+ /* Kept here for the purpose of making sure code doesn't break
+ x86 PVOPS */
+ BUG_ON(!((vma->vm_flags & (VM_PFNMAP | VM_IO)) == (VM_PFNMAP | VM_IO)));
- data.fgmfn = gfn;
- data.prot = prot;
+ data.fgmfn = mfn;
+ data.prot = prot;
data.domid = domid;
- data.vma = vma;
- data.index = 0;
+ data.vma = vma;
data.pages = pages;
- err = apply_to_page_range(vma->vm_mm, addr, nr << PAGE_SHIFT,
+ data.index = 0;
+ data.err_ptr = err_ptr;
+ data.mapped = 0;
+
+ err = apply_to_page_range(vma->vm_mm, addr, range,
remap_pte_fn, &data);
- return err;
+ return err < 0 ? err : data.mapped;
}
-EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_range);
+EXPORT_SYMBOL_GPL(xen_xlate_remap_gfn_array);
int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
int nr, struct page **pages)