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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2 1/3] xen: delay page scrubbing to allocation path
Because of page scrubbing, it's very slow to destroy a domain with large memory.
It takes around 10 minutes when destroy a guest of nearly 1 TB of memory.
This patch introduced a "PGC_need_scrub" flag, pages with this flag need to be
scrubbed before use. During domain destory just mark pages as "PGC_need_scrub"
and then add them to free list, so that xl can return quickly.
Note: PCG_need_scrub pages and normal pages are not mergeable
v2:
* Fix issue: Avoid to scrub all 4Tb when a 4Tb chunk found for a request of a
single page.
* Replace more scrub_one_page() place by setting "need_scrub"
* No more use an extra _scrub[] array
Signed-off-by: Bob Liu <bob.liu@xxxxxxxxxx>
---
xen/common/page_alloc.c | 63 ++++++++++++++++++++++++++++++++++------------
xen/include/asm-arm/mm.h | 5 +++-
xen/include/asm-x86/mm.h | 5 +++-
3 files changed, 55 insertions(+), 18 deletions(-)
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 58677d0..c184f86 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -711,6 +711,12 @@ static struct page_info *alloc_heap_pages(
for ( i = 0; i < (1 << order); i++ )
{
+ if ( test_bit(_PGC_need_scrub, &pg[i].count_info) )
+ {
+ scrub_one_page(&pg[i]);
+ pg[i].count_info &= ~PGC_need_scrub;
+ }
+
/* Reference count must continuously be zero for free pages. */
BUG_ON(pg[i].count_info != PGC_state_free);
pg[i].count_info = PGC_state_inuse;
@@ -827,7 +833,7 @@ static int reserve_offlined_page(struct page_info *head)
/* Free 2^@order set of pages. */
static void free_heap_pages(
- struct page_info *pg, unsigned int order)
+ struct page_info *pg, unsigned int order, bool_t need_scrub)
{
unsigned long mask, mfn = page_to_mfn(pg);
unsigned int i, node = phys_to_nid(page_to_maddr(pg)), tainted = 0;
@@ -876,6 +882,15 @@ static void free_heap_pages(
midsize_alloc_zone_pages = max(
midsize_alloc_zone_pages, total_avail_pages / MIDSIZE_ALLOC_FRAC);
+ if ( need_scrub )
+ {
+ if ( !tainted )
+ {
+ for ( i = 0; i < (1 << order); i++ )
+ pg[i].count_info |= PGC_need_scrub;
+ }
+ }
+
/* Merge chunks as far as possible. */
while ( order < MAX_ORDER )
{
@@ -889,6 +904,17 @@ static void free_heap_pages(
(PFN_ORDER(pg-mask) != order) ||
(phys_to_nid(page_to_maddr(pg-mask)) != node) )
break;
+ /* If we need scrub, only merge with PGC_need_scrub pages */
+ if ( need_scrub )
+ {
+ if ( !test_bit(_PGC_need_scrub, &(pg-mask)->count_info) )
+ break;
+ }
+ else
+ {
+ if ( test_bit(_PGC_need_scrub, &(pg-mask)->count_info) )
+ break;
+ }
pg -= mask;
page_list_del(pg, &heap(node, zone, order));
}
@@ -900,6 +926,16 @@ static void free_heap_pages(
(PFN_ORDER(pg+mask) != order) ||
(phys_to_nid(page_to_maddr(pg+mask)) != node) )
break;
+ if ( need_scrub )
+ {
+ if ( !test_bit(_PGC_need_scrub, &(pg+mask)->count_info) )
+ break;
+ }
+ else
+ {
+ if ( test_bit(_PGC_need_scrub, &(pg+mask)->count_info) )
+ break;
+ }
page_list_del(pg + mask, &heap(node, zone, order));
}
@@ -1132,7 +1168,7 @@ unsigned int online_page(unsigned long mfn, uint32_t
*status)
spin_unlock(&heap_lock);
if ( (y & PGC_state) == PGC_state_offlined )
- free_heap_pages(pg, 0);
+ free_heap_pages(pg, 0, 0);
return ret;
}
@@ -1201,7 +1237,7 @@ static void init_heap_pages(
nr_pages -= n;
}
- free_heap_pages(pg+i, 0);
+ free_heap_pages(pg+i, 0, 0);
}
}
@@ -1535,7 +1571,7 @@ void free_xenheap_pages(void *v, unsigned int order)
memguard_guard_range(v, 1 << (order + PAGE_SHIFT));
- free_heap_pages(virt_to_page(v), order);
+ free_heap_pages(virt_to_page(v), order, 1);
}
#else
@@ -1588,11 +1624,10 @@ void free_xenheap_pages(void *v, unsigned int order)
for ( i = 0; i < (1u << order); i++ )
{
- scrub_one_page(&pg[i]);
pg[i].count_info &= ~PGC_xen_heap;
}
- free_heap_pages(pg, order);
+ free_heap_pages(pg, order, 1);
}
#endif
@@ -1696,7 +1731,7 @@ struct page_info *alloc_domheap_pages(
if ( (d != NULL) && assign_pages(d, pg, order, memflags) )
{
- free_heap_pages(pg, order);
+ free_heap_pages(pg, order, 0);
return NULL;
}
@@ -1745,24 +1780,20 @@ void free_domheap_pages(struct page_info *pg, unsigned
int order)
* domain has died we assume responsibility for erasure.
*/
if ( unlikely(d->is_dying) )
- for ( i = 0; i < (1 << order); i++ )
- scrub_one_page(&pg[i]);
-
- free_heap_pages(pg, order);
+ free_heap_pages(pg, order, 1);
+ else
+ free_heap_pages(pg, order, 0);
}
else if ( unlikely(d == dom_cow) )
{
ASSERT(order == 0);
- scrub_one_page(pg);
- free_heap_pages(pg, 0);
+ free_heap_pages(pg, 0, 1);
drop_dom_ref = 0;
}
else
{
/* Freeing anonymous domain-heap pages. */
- for ( i = 0; i < (1 << order); i++ )
- scrub_one_page(&pg[i]);
- free_heap_pages(pg, order);
+ free_heap_pages(pg, order, 1);
drop_dom_ref = 0;
}
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index 2552d34..e8913a8 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -103,9 +103,12 @@ struct page_info
#define PGC_state_offlined PG_mask(2, 9)
#define PGC_state_free PG_mask(3, 9)
#define page_state_is(pg, st) (((pg)->count_info&PGC_state) == PGC_state_##st)
+/* Page need to be scrubbed */
+#define _PGC_need_scrub PG_shift(10)
+#define PGC_need_scrub PG_mask(1, 10)
/* Count of references to this frame. */
-#define PGC_count_width PG_shift(9)
+#define PGC_count_width PG_shift(10)
#define PGC_count_mask ((1UL<<PGC_count_width)-1)
extern unsigned long xenheap_mfn_start, xenheap_mfn_end;
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index d253117..35746ab 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -223,9 +223,12 @@ struct page_info
#define PGC_state_offlined PG_mask(2, 9)
#define PGC_state_free PG_mask(3, 9)
#define page_state_is(pg, st) (((pg)->count_info&PGC_state) == PGC_state_##st)
+/* Page need to be scrubbed */
+#define _PGC_need_scrub PG_shift(10)
+#define PGC_need_scrub PG_mask(1, 10)
/* Count of references to this frame. */
-#define PGC_count_width PG_shift(9)
+#define PGC_count_width PG_shift(10)
#define PGC_count_mask ((1UL<<PGC_count_width)-1)
struct spage_info
--
1.7.10.4
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