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authorJuergen Gross <jgross@suse.com>2014-11-28 11:53:58 +0100
committerDavid Vrabel <david.vrabel@citrix.com>2014-12-04 14:09:15 +0000
commit054954eb051f35e74b75a566a96fe756015352c8 (patch)
treedf657656b63e19dbfa2bbf7bb21f87e45d3d3ddc /arch/x86/xen/xen-ops.h
parent0aad5689837c882d2539f50f42f686b74046c0a0 (diff)
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xen: switch to linear virtual mapped sparse p2m list
At start of the day the Xen hypervisor presents a contiguous mfn list to a pv-domain. In order to support sparse memory this mfn list is accessed via a three level p2m tree built early in the boot process. Whenever the system needs the mfn associated with a pfn this tree is used to find the mfn. Instead of using a software walked tree for accessing a specific mfn list entry this patch is creating a virtual address area for the entire possible mfn list including memory holes. The holes are covered by mapping a pre-defined page consisting only of "invalid mfn" entries. Access to a mfn entry is possible by just using the virtual base address of the mfn list and the pfn as index into that list. This speeds up the (hot) path of determining the mfn of a pfn. Kernel build on a Dell Latitude E6440 (2 cores, HT) in 64 bit Dom0 showed following improvements: Elapsed time: 32:50 -> 32:35 System: 18:07 -> 17:47 User: 104:00 -> 103:30 Tested with following configurations: - 64 bit dom0, 8GB RAM - 64 bit dom0, 128 GB RAM, PCI-area above 4 GB - 32 bit domU, 512 MB, 8 GB, 43 GB (more wouldn't work even without the patch) - 32 bit domU, ballooning up and down - 32 bit domU, save and restore - 32 bit domU with PCI passthrough - 64 bit domU, 8 GB, 2049 MB, 5000 MB - 64 bit domU, ballooning up and down - 64 bit domU, save and restore - 64 bit domU with PCI passthrough Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'arch/x86/xen/xen-ops.h')
-rw-r--r--arch/x86/xen/xen-ops.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 02b0b0fba041..f92921fa54f9 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -49,7 +49,7 @@ void xen_hvm_init_shared_info(void);
void xen_unplug_emulated_devices(void);
void __init xen_build_dynamic_phys_to_machine(void);
-unsigned long __init xen_revector_p2m_tree(void);
+void __init xen_vmalloc_p2m_tree(void);
void xen_init_irq_ops(void);
void xen_setup_timer(int cpu);