# HG changeset patch
# User George Dunlap <george.dunlap@xxxxxxxxxxxxx>
# Date 1295274541 0
# Node ID 3decd02e0b18ae21fb926c6bad96a4cd02c48272
# Parent 97ab84aca65cdcbce2ddccc51629fb24adb056cf
PoD,hap: Fix logdirty mode when using hardware assisted paging
When writing a writable p2m entry for a pfn, we need to mark the pfn
dirty to avoid corruption when doing live migration.
Marking the page dirty exposes another issue, where there are
excessive sweeps for zero pages if there's a mismatch between PoD
entries and cache entries. Only sweep for zero pages if we actually
need more memory.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
Acked-by: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
---
xen/arch/x86/mm/p2m.c | 27 +++++++++++++++++++--------
1 files changed, 19 insertions(+), 8 deletions(-)
diff -r 97ab84aca65c -r 3decd02e0b18 xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c Mon Jan 17 14:24:13 2011 +0000
+++ b/xen/arch/x86/mm/p2m.c Mon Jan 17 14:29:01 2011 +0000
@@ -1142,14 +1142,22 @@ p2m_pod_demand_populate(struct p2m_domai
return 0;
}
- /* If we're low, start a sweep */
- if ( order == 9 && page_list_empty(&p2m->pod.super) )
- p2m_pod_emergency_sweep_super(p2m);
-
- if ( page_list_empty(&p2m->pod.single) &&
- ( ( order == 0 )
- || (order == 9 && page_list_empty(&p2m->pod.super) ) ) )
- p2m_pod_emergency_sweep(p2m);
+ /* Once we've ballooned down enough that we can fill the remaining
+ * PoD entries from the cache, don't sweep even if the particular
+ * list we want to use is empty: that can lead to thrashing zero pages
+ * through the cache for no good reason. */
+ if ( p2m->pod.entry_count > p2m->pod.count )
+ {
+
+ /* If we're low, start a sweep */
+ if ( order == 9 && page_list_empty(&p2m->pod.super) )
+ p2m_pod_emergency_sweep_super(p2m);
+
+ if ( page_list_empty(&p2m->pod.single) &&
+ ( ( order == 0 )
+ || (order == 9 && page_list_empty(&p2m->pod.super) ) ) )
+ p2m_pod_emergency_sweep(p2m);
+ }
/* Keep track of the highest gfn demand-populated by a guest fault */
if ( q == p2m_guest && gfn > p2m->pod.max_guest )
@@ -1176,7 +1184,10 @@ p2m_pod_demand_populate(struct p2m_domai
set_p2m_entry(p2m, gfn_aligned, mfn, order, p2m_ram_rw,
p2m->default_access);
for( i = 0; i < (1UL << order); i++ )
+ {
set_gpfn_from_mfn(mfn_x(mfn) + i, gfn_aligned + i);
+ paging_mark_dirty(d, mfn_x(mfn) + i);
+ }
p2m->pod.entry_count -= (1 << order); /* Lock: p2m */
BUG_ON(p2m->pod.entry_count < 0);
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