# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1233233313 0
# Node ID 259d6ac137042b47e36b37c6a1692e4835348108
# Parent 31798b19f25c1209f8a266127df3e77f71af09b6
PoD: Remove on-stack arrays from pod_zero_check_superpage
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
---
xen/arch/x86/mm/p2m.c | 67 ++++++++++++++++++++++++++------------------------
1 files changed, 35 insertions(+), 32 deletions(-)
diff -r 31798b19f25c -r 259d6ac13704 xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c Thu Jan 29 12:44:31 2009 +0000
+++ b/xen/arch/x86/mm/p2m.c Thu Jan 29 12:48:33 2009 +0000
@@ -713,14 +713,15 @@ p2m_pod_dump_data(struct domain *d)
#define superpage_aligned(_x) (((_x)&((1<<9)-1))==0)
-/* Must be called w/ p2m lock held, page_alloc lock not held */
+/* Search for all-zero superpages to be reclaimed as superpages for the
+ * PoD cache. Must be called w/ p2m lock held, page_alloc lock not held. */
static int
p2m_pod_zero_check_superpage(struct domain *d, unsigned long gfn)
{
- mfn_t mfns[1<<9];
- p2m_type_t types[1<<9];
- unsigned long * map[1<<9] = { NULL };
- int ret=0, reset = 0, reset_max = 0;
+ mfn_t mfn, mfn0 = _mfn(INVALID_MFN);
+ p2m_type_t type, type0 = 0;
+ unsigned long * map = NULL;
+ int ret=0, reset = 0;
int i, j;
if ( !superpage_aligned(gfn) )
@@ -730,7 +731,14 @@ p2m_pod_zero_check_superpage(struct doma
* and aligned, and mapping them. */
for ( i=0; i<(1<<9); i++ )
{
- mfns[i] = gfn_to_mfn_query(d, gfn + i, types + i);
+
+ mfn = gfn_to_mfn_query(d, gfn + i, &type);
+
+ if ( i == 0 )
+ {
+ mfn0 = mfn;
+ type0 = type;
+ }
/* Conditions that must be met for superpage-superpage:
* + All gfns are ram types
@@ -739,36 +747,37 @@ p2m_pod_zero_check_superpage(struct doma
* + The first mfn is 2-meg aligned
* + All the other mfns are in sequence
*/
- if ( p2m_is_ram(types[i])
- && types[i] == types[0]
- && ( (mfn_to_page(mfns[i])->count_info & PGC_page_table) == 0 )
- && ( ( i == 0 && superpage_aligned(mfn_x(mfns[0])) )
- || ( i != 0 && mfn_x(mfns[i]) == mfn_x(mfns[0]) + i ) ) )
- map[i] = map_domain_page(mfn_x(mfns[i]));
- else
- goto out_unmap;
+ if ( !p2m_is_ram(type)
+ || type != type0
+ || ( (mfn_to_page(mfn)->count_info & PGC_page_table) != 0 )
+ || !( ( i == 0 && superpage_aligned(mfn_x(mfn0)) )
+ || ( i != 0 && mfn_x(mfn) == (mfn_x(mfn0) + i) ) ) )
+ goto out;
}
/* Now, do a quick check to see if it may be zero before unmapping. */
for ( i=0; i<(1<<9); i++ )
{
/* Quick zero-check */
+ map = map_domain_page(mfn_x(mfn0) + i);
+
for ( j=0; j<16; j++ )
- if( *(map[i]+j) != 0 )
+ if( *(map+j) != 0 )
break;
+ unmap_domain_page(map);
+
if ( j < 16 )
- goto out_unmap;
+ goto out;
}
/* Try to remove the page, restoring old mapping if it fails. */
- reset_max = 1<<9;
set_p2m_entry(d, gfn,
_mfn(POPULATE_ON_DEMAND_MFN), 9,
p2m_populate_on_demand);
- if ( (mfn_to_page(mfns[0])->u.inuse.type_info & PGT_count_mask) != 0 )
+ if ( (mfn_to_page(mfn0)->u.inuse.type_info & PGT_count_mask) != 0 )
{
reset = 1;
goto out_reset;
@@ -793,36 +802,30 @@ p2m_pod_zero_check_superpage(struct doma
/* Finally, do a full zero-check */
for ( i=0; i < (1<<9); i++ )
{
- for ( j=0; j<PAGE_SIZE/sizeof(*map[i]); j++ )
- if( *(map[i]+j) != 0 )
+ map = map_domain_page(mfn_x(mfn0) + i);
+
+ for ( j=0; j<PAGE_SIZE/sizeof(*map); j++ )
+ if( *(map+j) != 0 )
{
reset = 1;
break;
}
+ unmap_domain_page(map);
+
if ( reset )
goto out_reset;
}
/* Finally! We've passed all the checks, and can add the mfn superpage
* back on the PoD cache, and account for the new p2m PoD entries */
- p2m_pod_cache_add(d, mfn_to_page(mfns[0]), 9);
+ p2m_pod_cache_add(d, mfn_to_page(mfn0), 9);
d->arch.p2m->pod.entry_count += (1<<9);
out_reset:
if ( reset )
- {
- if (reset_max == (1<<9) )
- set_p2m_entry(d, gfn, mfns[0], 9, types[0]);
- else
- for ( i=0; i<reset_max; i++)
- set_p2m_entry(d, gfn + i, mfns[i], 0, types[i]);
- }
+ set_p2m_entry(d, gfn, mfn0, 9, type0);
-out_unmap:
- for ( i=0; i<(1<<9); i++ )
- if ( map[i] )
- unmap_domain_page(map[i]);
out:
return ret;
}
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