# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1231152230 0
# Node ID bd33ff263e2cf2d09f9ece01831a41af79019f63
# Parent f2ba08549466d595fd5901ad655ebe82c266753d
PoD memory 4/9: Decrease reservation
Handle balloon driver's calls to decrease_reservation properly.
* Replace PoD entries with p2m_none
* Steal memory for the cache instead of freeing, if need be
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
---
xen/arch/x86/mm/p2m.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++
xen/common/memory.c | 5 +
xen/include/asm-x86/p2m.h | 7 ++
3 files changed, 135 insertions(+)
diff -r f2ba08549466 -r bd33ff263e2c xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c Mon Jan 05 10:43:19 2009 +0000
+++ b/xen/arch/x86/mm/p2m.c Mon Jan 05 10:43:50 2009 +0000
@@ -253,6 +253,10 @@ p2m_next_level(struct domain *d, mfn_t *
/*
* Populate-on-demand functionality
*/
+static
+int set_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn,
+ unsigned int page_order, p2m_type_t p2mt);
+
int
p2m_pod_cache_add(struct domain *d,
struct page_info *page,
@@ -362,6 +366,125 @@ p2m_pod_empty_cache(struct domain *d)
BUG_ON(p2md->pod.count != 0);
spin_unlock(&d->page_alloc_lock);
+}
+
+/* This function is needed for two reasons:
+ * + To properly handle clearing of PoD entries
+ * + To "steal back" memory being freed for the PoD cache, rather than
+ * releasing it.
+ *
+ * Once both of these functions have been completed, we can return and
+ * allow decrease_reservation() to handle everything else.
+ */
+int
+p2m_pod_decrease_reservation(struct domain *d,
+ xen_pfn_t gpfn,
+ unsigned int order)
+{
+ struct p2m_domain *p2md = d->arch.p2m;
+ int ret=0;
+ int i;
+
+ int steal_for_cache = 0;
+ int pod = 0, nonpod = 0, ram = 0;
+
+
+ /* If we don't have any outstanding PoD entries, let things take their
+ * course */
+ if ( p2md->pod.entry_count == 0 )
+ goto out;
+
+ /* Figure out if we need to steal some freed memory for our cache */
+ steal_for_cache = ( p2md->pod.entry_count > p2md->pod.count );
+
+ p2m_lock(p2md);
+ audit_p2m(d);
+
+ /* See what's in here. */
+ /* FIXME: Add contiguous; query for PSE entries? */
+ for ( i=0; i<(1<<order); i++)
+ {
+ p2m_type_t t;
+
+ gfn_to_mfn_query(d, gpfn + i, &t);
+
+ if ( t == p2m_populate_on_demand )
+ pod++;
+ else
+ {
+ nonpod++;
+ if ( p2m_is_ram(t) )
+ ram++;
+ }
+ }
+
+ /* No populate-on-demand? Don't need to steal anything? Then we're
done!*/
+ if(!pod && !steal_for_cache)
+ goto out_unlock;
+
+ if ( !nonpod )
+ {
+ /* All PoD: Mark the whole region invalid and tell caller
+ * we're done. */
+ set_p2m_entry(d, gpfn, _mfn(INVALID_MFN), order, p2m_invalid);
+ p2md->pod.entry_count-=(1<<order); /* Lock: p2m */
+ BUG_ON(p2md->pod.entry_count < 0);
+ ret = 1;
+ goto out_unlock;
+ }
+
+ /* FIXME: Steal contig 2-meg regions for cache */
+
+ /* Process as long as:
+ * + There are PoD entries to handle, or
+ * + There is ram left, and we want to steal it
+ */
+ for ( i=0;
+ i<(1<<order) && (pod>0 || (steal_for_cache && ram > 0));
+ i++)
+ {
+ mfn_t mfn;
+ p2m_type_t t;
+
+ mfn = gfn_to_mfn_query(d, gpfn + i, &t);
+ if ( t == p2m_populate_on_demand )
+ {
+ set_p2m_entry(d, gpfn + i, _mfn(INVALID_MFN), 0, p2m_invalid);
+ p2md->pod.entry_count--; /* Lock: p2m */
+ BUG_ON(p2md->pod.entry_count < 0);
+ pod--;
+ }
+ else if ( steal_for_cache && p2m_is_ram(t) )
+ {
+ struct page_info *page;
+
+ ASSERT(mfn_valid(mfn));
+
+ page = mfn_to_page(mfn);
+
+ set_p2m_entry(d, gpfn + i, _mfn(INVALID_MFN), 0, p2m_invalid);
+ set_gpfn_from_mfn(mfn_x(mfn), INVALID_M2P_ENTRY);
+
+ p2m_pod_cache_add(d, page, 0);
+
+ steal_for_cache = ( p2md->pod.entry_count > p2md->pod.count );
+
+ nonpod--;
+ ram--;
+ }
+ }
+
+ /* If there are no more non-PoD entries, tell decrease_reservation() that
+ * there's nothing left to do. */
+ if ( nonpod == 0 )
+ ret = 1;
+
+out_unlock:
+ audit_p2m(d);
+ p2m_unlock(p2md);
+
+out:
+ return ret;
}
void
diff -r f2ba08549466 -r bd33ff263e2c xen/common/memory.c
--- a/xen/common/memory.c Mon Jan 05 10:43:19 2009 +0000
+++ b/xen/common/memory.c Mon Jan 05 10:43:50 2009 +0000
@@ -192,6 +192,11 @@ static void decrease_reservation(struct
if ( unlikely(__copy_from_guest_offset(&gmfn, a->extent_list, i, 1)) )
goto out;
+ /* See if populate-on-demand wants to handle this */
+ if ( is_hvm_domain(a->domain)
+ && p2m_pod_decrease_reservation(a->domain, gmfn, a->extent_order)
)
+ continue;
+
for ( j = 0; j < (1 << a->extent_order); j++ )
if ( !guest_remove_page(a->domain, gmfn + j) )
goto out;
diff -r f2ba08549466 -r bd33ff263e2c xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h Mon Jan 05 10:43:19 2009 +0000
+++ b/xen/include/asm-x86/p2m.h Mon Jan 05 10:43:50 2009 +0000
@@ -258,6 +258,13 @@ void p2m_pod_dump_data(struct domain *d)
* (usually in preparation for domain destruction) */
void p2m_pod_empty_cache(struct domain *d);
+/* Call when decreasing memory reservation to handle PoD entries properly.
+ * Will return '1' if all entries were handled and nothing more need be done.*/
+int
+p2m_pod_decrease_reservation(struct domain *d,
+ xen_pfn_t gpfn,
+ unsigned int order);
+
/* Add a page to a domain's p2m table */
int guest_physmap_add_entry(struct domain *d, unsigned long gfn,
unsigned long mfn, unsigned int page_order,
_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog
|
Home