ChangeSet 1.1802, 2005/03/22 19:26:37+00:00, kaf24@xxxxxxxxxxxxxxxxxxxx
Schedule page scrubbing for dead domains off the per-cpu periodic
ticker. We take 10% of busy cpus and all of idle cpu time.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
arch/x86/domain.c | 3 +
common/page_alloc.c | 89 +++++++++++++++++++++++++++++++++++++++++++-------
common/schedule.c | 2 +
include/xen/mm.h | 13 +++++++
include/xen/softirq.h | 3 +
5 files changed, 97 insertions(+), 13 deletions(-)
diff -Nru a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c 2005-03-22 15:05:39 -05:00
+++ b/xen/arch/x86/domain.c 2005-03-22 15:05:39 -05:00
@@ -69,7 +69,10 @@
{
irq_stat[cpu].idle_timestamp = jiffies;
while ( !softirq_pending(cpu) )
+ {
+ page_scrub_schedule_work();
default_idle();
+ }
do_softirq();
}
}
diff -Nru a/xen/common/page_alloc.c b/xen/common/page_alloc.c
--- a/xen/common/page_alloc.c 2005-03-22 15:05:39 -05:00
+++ b/xen/common/page_alloc.c 2005-03-22 15:05:39 -05:00
@@ -28,6 +28,7 @@
#include <xen/spinlock.h>
#include <xen/slab.h>
#include <xen/irq.h>
+#include <xen/softirq.h>
#include <asm/domain_page.h>
/*
@@ -551,7 +552,6 @@
{
int i, drop_dom_ref;
struct domain *d = pg->u.inuse.domain;
- void *p;
ASSERT(!in_irq());
@@ -579,26 +579,31 @@
pg[i].tlbflush_timestamp = tlbflush_current_time();
pg[i].u.free.cpu_mask = 1 << d->processor;
list_del(&pg[i].list);
+ }
+
+ d->tot_pages -= 1 << order;
+ drop_dom_ref = (d->tot_pages == 0);
+
+ spin_unlock_recursive(&d->page_alloc_lock);
+ if ( likely(!test_bit(DF_DYING, &d->flags)) )
+ {
+ free_heap_pages(MEMZONE_DOM, pg, order);
+ }
+ else
+ {
/*
* Normally we expect a domain to clear pages before freeing them,
* if it cares about the secrecy of their contents. However, after
* a domain has died we assume responsibility for erasure.
*/
- if ( unlikely(test_bit(DF_DYING, &d->flags)) )
+ for ( i = 0; i < (1 << order); i++ )
{
- p = map_domain_mem(page_to_phys(&pg[i]));
- clear_page(p);
- unmap_domain_mem(p);
+ spin_lock(&page_scrub_lock);
+ list_add(&pg[i].list, &page_scrub_list);
+ spin_unlock(&page_scrub_lock);
}
}
-
- d->tot_pages -= 1 << order;
- drop_dom_ref = (d->tot_pages == 0);
-
- spin_unlock_recursive(&d->page_alloc_lock);
-
- free_heap_pages(MEMZONE_DOM, pg, order);
}
else
{
@@ -616,3 +621,63 @@
{
return avail[MEMZONE_DOM];
}
+
+
+
+/*************************
+ * PAGE SCRUBBING
+ */
+
+static spinlock_t page_scrub_lock;
+struct list_head page_scrub_list;
+
+static void page_scrub_softirq(void)
+{
+ struct list_head *ent;
+ struct pfn_info *pg;
+ void *p;
+ int i;
+ s_time_t start = NOW();
+
+ /* Aim to do 1ms of work (ten percent of a 10ms jiffy). */
+ do {
+ spin_lock(&page_scrub_lock);
+
+ if ( unlikely((ent = page_scrub_list.next) == &page_scrub_list) )
+ {
+ spin_unlock(&page_scrub_lock);
+ return;
+ }
+
+ /* Peel up to 16 pages from the list. */
+ for ( i = 0; i < 16; i++ )
+ if ( (ent = ent->next) == &page_scrub_list )
+ break;
+
+ /* Remove peeled pages from the list. */
+ ent->next->prev = &page_scrub_list;
+ page_scrub_list.next = ent->next;
+
+ spin_unlock(&page_scrub_lock);
+
+ /* Working backwards, scrub each page in turn. */
+ while ( ent != &page_scrub_list )
+ {
+ pg = list_entry(ent, struct pfn_info, list);
+ ent = ent->prev;
+ p = map_domain_mem(page_to_phys(pg));
+ clear_page(p);
+ unmap_domain_mem(p);
+ free_heap_pages(MEMZONE_DOM, pg, 0);
+ }
+ } while ( (NOW() - start) < MILLISECS(1) );
+}
+
+static __init int page_scrub_init(void)
+{
+ spin_lock_init(&page_scrub_lock);
+ INIT_LIST_HEAD(&page_scrub_list);
+ open_softirq(PAGE_SCRUB_SOFTIRQ, page_scrub_softirq);
+ return 0;
+}
+__initcall(page_scrub_init);
diff -Nru a/xen/common/schedule.c b/xen/common/schedule.c
--- a/xen/common/schedule.c 2005-03-22 15:05:39 -05:00
+++ b/xen/common/schedule.c 2005-03-22 15:05:39 -05:00
@@ -437,6 +437,8 @@
if ( !is_idle_task(d) && update_dom_time(d) )
send_guest_virq(d, VIRQ_TIMER);
+ page_scrub_schedule_work();
+
t_timer[d->processor].expires = NOW() + MILLISECS(10);
add_ac_timer(&t_timer[d->processor]);
}
diff -Nru a/xen/include/xen/mm.h b/xen/include/xen/mm.h
--- a/xen/include/xen/mm.h 2005-03-22 15:05:39 -05:00
+++ b/xen/include/xen/mm.h 2005-03-22 15:05:39 -05:00
@@ -2,6 +2,10 @@
#ifndef __XEN_MM_H__
#define __XEN_MM_H__
+#include <xen/config.h>
+#include <xen/list.h>
+#include <xen/spinlock.h>
+
struct domain;
struct pfn_info;
@@ -33,6 +37,15 @@
unsigned long avail_domheap_pages(void);
#define alloc_domheap_page(_d) (alloc_domheap_pages(_d,0))
#define free_domheap_page(_p) (free_domheap_pages(_p,0))
+
+/* Automatic page scrubbing for dead domains. */
+extern spinlock_t page_scrub_lock;
+extern struct list_head page_scrub_list;
+#define page_scrub_schedule_work() \
+ do { \
+ if ( !list_empty(&page_scrub_list) ) \
+ raise_softirq(PAGE_SCRUB_SOFTIRQ); \
+ } while ( 0 )
#include <asm/mm.h>
diff -Nru a/xen/include/xen/softirq.h b/xen/include/xen/softirq.h
--- a/xen/include/xen/softirq.h 2005-03-22 15:05:39 -05:00
+++ b/xen/include/xen/softirq.h 2005-03-22 15:05:39 -05:00
@@ -7,7 +7,8 @@
#define NEW_TLBFLUSH_CLOCK_PERIOD_SOFTIRQ 2
#define KEYPRESS_SOFTIRQ 3
#define NMI_SOFTIRQ 4
-#define NR_SOFTIRQS 5
+#define PAGE_SCRUB_SOFTIRQ 5
+#define NR_SOFTIRQS 6
#ifndef __ASSEMBLY__
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