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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 2/9] mm: Place unscrubbed pages at the end of pagelist
. so that it's easy to find pages that need to be scrubbed (those pages are
now marked with _PGC_need_scrub bit).
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
Changes in v3:
* Keep dirty bit per page, add dirty_head to page_info that indicates whether
the buddy has dirty pages.
* Make page_list_add_scrub() set buddy's page order
* Data type adjustments (int -> unsigned)
xen/common/page_alloc.c | 119 +++++++++++++++++++++++++++++++++++++--------
xen/include/asm-arm/mm.h | 6 ++
xen/include/asm-x86/mm.h | 6 ++
3 files changed, 110 insertions(+), 21 deletions(-)
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 6fe55ee..9dcf6ee 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -383,6 +383,8 @@ typedef struct page_list_head
heap_by_zone_and_order_t[NR_ZONES][MAX_ORDER+1];
static heap_by_zone_and_order_t *_heap[MAX_NUMNODES];
#define heap(node, zone, order) ((*_heap[node])[zone][order])
+static unsigned long node_need_scrub[MAX_NUMNODES];
+
static unsigned long *avail[MAX_NUMNODES];
static long total_avail_pages;
@@ -678,6 +680,20 @@ static void check_low_mem_virq(void)
}
}
+/* Pages that need scrub are added to tail, otherwise to head. */
+static void page_list_add_scrub(struct page_info *pg, unsigned int node,
+ unsigned int zone, unsigned int order,
+ bool need_scrub)
+{
+ PFN_ORDER(pg) = order;
+ pg->u.free.dirty_head = need_scrub;
+
+ if ( need_scrub )
+ page_list_add_tail(pg, &heap(node, zone, order));
+ else
+ page_list_add(pg, &heap(node, zone, order));
+}
+
/* Allocate 2^@order contiguous pages. */
static struct page_info *alloc_heap_pages(
unsigned int zone_lo, unsigned int zone_hi,
@@ -802,7 +818,7 @@ static struct page_info *alloc_heap_pages(
while ( j != order )
{
PFN_ORDER(pg) = --j;
- page_list_add_tail(pg, &heap(node, zone, j));
+ page_list_add(pg, &heap(node, zone, j));
pg += 1 << j;
}
@@ -851,11 +867,14 @@ static int reserve_offlined_page(struct page_info *head)
int zone = page_to_zone(head), i, head_order = PFN_ORDER(head), count = 0;
struct page_info *cur_head;
int cur_order;
+ bool need_scrub;
ASSERT(spin_is_locked(&heap_lock));
cur_head = head;
+ head->u.free.dirty_head = false;
+
page_list_del(head, &heap(node, zone, head_order));
while ( cur_head < (head + (1 << head_order)) )
@@ -892,8 +911,16 @@ static int reserve_offlined_page(struct page_info *head)
{
merge:
/* We don't consider merging outside the head_order. */
- page_list_add_tail(cur_head, &heap(node, zone, cur_order));
- PFN_ORDER(cur_head) = cur_order;
+
+ /* See if any of the pages need scrubbing. */
+ need_scrub = false;
+ for ( i = 0; i < (1 << cur_order); i++ )
+ if ( test_bit(_PGC_need_scrub, &cur_head[i].count_info) )
+ {
+ need_scrub = true;
+ break;
+ }
+ page_list_add_scrub(cur_head, node, zone, cur_order,
need_scrub);
cur_head += (1 << cur_order);
break;
}
@@ -922,10 +949,13 @@ static int reserve_offlined_page(struct page_info *head)
/* Returns new buddy head. */
static struct page_info *
merge_and_free_buddy(struct page_info *pg, unsigned int node,
- unsigned int zone, unsigned int order)
+ unsigned int zone, unsigned int order,
+ bool need_scrub)
{
ASSERT(spin_is_locked(&heap_lock));
+ pg->u.free.dirty_head = false;
+
/* Merge chunks as far as possible. */
while ( order < MAX_ORDER )
{
@@ -944,6 +974,8 @@ merge_and_free_buddy(struct page_info *pg, unsigned int
node,
break;
page_list_del(buddy, &heap(node, zone, order));
+ need_scrub |= buddy->u.free.dirty_head;
+ buddy->u.free.dirty_head = false;
/* Adjust current buddy head if we merged backwards. */
if ( buddy < pg )
@@ -952,15 +984,56 @@ merge_and_free_buddy(struct page_info *pg, unsigned int
node,
order++;
}
- PFN_ORDER(pg) = order;
- page_list_add_tail(pg, &heap(node, zone, order));
+ page_list_add_scrub(pg, node, zone, order, need_scrub);
return pg;
}
+static void scrub_free_pages(unsigned int node)
+{
+ struct page_info *pg;
+ unsigned int zone, order;
+ unsigned long i;
+
+ ASSERT(spin_is_locked(&heap_lock));
+
+ if ( !node_need_scrub[node] )
+ return;
+
+ for ( zone = 0; zone < NR_ZONES; zone++ )
+ {
+ order = MAX_ORDER;
+ do {
+ while ( !page_list_empty(&heap(node, zone, order)) )
+ {
+ /* Unscrubbed pages are always at the end of the list. */
+ pg = page_list_last(&heap(node, zone, order));
+ if ( !pg->u.free.dirty_head )
+ break;
+
+ for ( i = 0; i < (1UL << order); i++)
+ {
+ if ( test_bit(_PGC_need_scrub, &pg[i].count_info) )
+ {
+ scrub_one_page(&pg[i]);
+ pg[i].count_info &= ~PGC_need_scrub;
+ node_need_scrub[node]--;
+ }
+ }
+
+ page_list_del(pg, &heap(node, zone, order));
+ merge_and_free_buddy(pg, node, zone, order, false);
+
+ if ( node_need_scrub[node] == 0 )
+ return;
+ }
+ } while ( order-- != 0 );
+ }
+}
+
/* 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 need_scrub)
{
unsigned long mfn = page_to_mfn(pg);
unsigned int i, node = phys_to_nid(page_to_maddr(pg)), tainted = 0;
@@ -1009,11 +1082,22 @@ static void free_heap_pages(
midsize_alloc_zone_pages = max(
midsize_alloc_zone_pages, total_avail_pages / MIDSIZE_ALLOC_FRAC);
- pg = merge_and_free_buddy(pg, node, zone, order);
+ if ( need_scrub )
+ {
+ for ( i = 0; i < (1 << order); i++ )
+ pg[i].count_info |= PGC_need_scrub;
+
+ node_need_scrub[node] += (1UL << order);
+ }
+
+ pg = merge_and_free_buddy(pg, node, zone, order, need_scrub);
if ( tainted )
reserve_offlined_page(pg);
+ if ( need_scrub )
+ scrub_free_pages(node);
+
spin_unlock(&heap_lock);
}
@@ -1234,7 +1318,7 @@ 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, false);
return ret;
}
@@ -1303,7 +1387,7 @@ static void init_heap_pages(
nr_pages -= n;
}
- free_heap_pages(pg+i, 0);
+ free_heap_pages(pg + i, 0, false);
}
}
@@ -1630,7 +1714,7 @@ 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, false);
}
#else
@@ -1684,12 +1768,9 @@ void free_xenheap_pages(void *v, unsigned int order)
pg = virt_to_page(v);
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, true);
}
#endif
@@ -1798,7 +1879,7 @@ struct page_info *alloc_domheap_pages(
if ( d && !(memflags & MEMF_no_owner) &&
assign_pages(d, pg, order, memflags) )
{
- free_heap_pages(pg, order);
+ free_heap_pages(pg, order, false);
return NULL;
}
@@ -1866,11 +1947,7 @@ void free_domheap_pages(struct page_info *pg, unsigned
int order)
scrub = 1;
}
- if ( unlikely(scrub) )
- for ( i = 0; i < (1 << order); i++ )
- scrub_one_page(&pg[i]);
-
- free_heap_pages(pg, order);
+ free_heap_pages(pg, order, scrub);
}
if ( drop_dom_ref )
diff --git a/xen/include/asm-arm/mm.h b/xen/include/asm-arm/mm.h
index 0fef612..abc3f6b 100644
--- a/xen/include/asm-arm/mm.h
+++ b/xen/include/asm-arm/mm.h
@@ -45,6 +45,8 @@ struct page_info
struct {
/* Do TLBs need flushing for safety before next page use? */
bool_t need_tlbflush;
+ /* Set on a buddy head if the buddy has unscrubbed pages. */
+ bool dirty_head;
} free;
} u;
@@ -115,6 +117,10 @@ struct page_info
#define PGC_count_width PG_shift(9)
#define PGC_count_mask ((1UL<<PGC_count_width)-1)
+/* Page needs to be scrubbed */
+#define _PGC_need_scrub PG_shift(10)
+#define PGC_need_scrub PG_mask(1, 10)
+
extern unsigned long xenheap_mfn_start, xenheap_mfn_end;
extern vaddr_t xenheap_virt_end;
#ifdef CONFIG_ARM_64
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index 119d7de..5cf528a 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -89,6 +89,8 @@ struct page_info
struct {
/* Do TLBs need flushing for safety before next page use? */
bool_t need_tlbflush;
+ /* Set on a buddy head if the buddy has unscrubbed pages. */
+ bool dirty_head;
} free;
} u;
@@ -233,6 +235,10 @@ struct page_info
#define PGC_count_width PG_shift(9)
#define PGC_count_mask ((1UL<<PGC_count_width)-1)
+/* Page needs to be scrubbed */
+#define _PGC_need_scrub PG_shift(10)
+#define PGC_need_scrub PG_mask(1, 10)
+
struct spage_info
{
unsigned long type_info;
--
1.7.1
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