[Xen-changelog] [xen-4.1-testing] [shadow] Disable higher level pagetables early unshadow only when the "process dying" hypercall is used.

[Xen patchbot-4.1-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User Gianluca Guida <gianluca.guida@xxxxxxxxxx>
# Date 1321461507 0
# Node ID efd132eee40c96a991bc8f354d39a186b6de3219
# Parent  4a91cf045893035f8cfd7f97ab6c134250d8411a
[shadow] Disable higher level pagetables early unshadow only when the "process 
dying" hypercall is used.

This patch fixes a performance problem in fully virtualized guests.

Signed-off-by: Gianluca Guida <gianluca.guida@xxxxxxxxxx>
Tested-by: Jan Beulich <jbeulich@xxxxxxxx>
Committed-by: Keir Fraser <keir@xxxxxxx>
xen-unstable changeset:   24148:3ecc8fef4281
xen-unstable date:        Wed Nov 16 15:19:33 2011 +0000
---


diff -r 4a91cf045893 -r efd132eee40c xen/arch/x86/mm/shadow/multi.c
--- a/xen/arch/x86/mm/shadow/multi.c    Wed Nov 16 16:37:49 2011 +0000
+++ b/xen/arch/x86/mm/shadow/multi.c    Wed Nov 16 16:38:27 2011 +0000
@@ -2743,8 +2743,9 @@
            || ( !v->domain->arch.paging.shadow.pagetable_dying_op
                 && v->arch.paging.shadow.last_emulated_mfn_for_unshadow == 
mfn_x(gmfn) ) )
          && sh_mfn_is_a_page_table(gmfn)
-         && !(mfn_to_page(gmfn)->shadow_flags
-              & (SHF_L2_32|SHF_L2_PAE|SHF_L2H_PAE|SHF_L4_64)) )
+         && (!v->domain->arch.paging.shadow.pagetable_dying_op ||
+             !(mfn_to_page(gmfn)->shadow_flags
+               & (SHF_L2_32|SHF_L2_PAE|SHF_L2H_PAE|SHF_L4_64))) )
     {
         perfc_incr(shadow_early_unshadow);
         sh_remove_shadows(v, gmfn, 1, 0 /* Fast, can fail to unshadow */ );

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog