Hi Penny,
On 18/05/2021 06:21, Penny Zheng wrote:
Since page_list under struct domain refers to linked pages as gueast RAM
s/gueast/guest/
allocated from heap, it should not include reserved pages of static memory.
You already have PGC_reserved to indicate they are "static memory". So
why do you need yet another list?
The number of PGC_reserved pages assigned to a domain is tracked in
a new 'reserved_pages' counter. Also introduce a new reserved_page_list
to link pages of static memory. Let page_to_list return reserved_page_list,
when flag is PGC_reserved.
Later, when domain get destroyed or restarted, those new values will help
relinquish memory to proper place, not been given back to heap.
Signed-off-by: Penny Zheng <penny.zh...@arm.com>
---
xen/common/domain.c | 1 +
xen/common/page_alloc.c | 7 +++++--
xen/include/xen/sched.h | 5 +++++
3 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 6b71c6d6a9..c38afd2969 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -578,6 +578,7 @@ struct domain *domain_create(domid_t domid,
INIT_PAGE_LIST_HEAD(&d->page_list);
INIT_PAGE_LIST_HEAD(&d->extra_page_list);
INIT_PAGE_LIST_HEAD(&d->xenpage_list);
+ INIT_PAGE_LIST_HEAD(&d->reserved_page_list);
spin_lock_init(&d->node_affinity_lock);
d->node_affinity = NODE_MASK_ALL;
diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index f1f1296a61..e3f07ec6c5 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -2410,7 +2410,7 @@ int assign_pages(
for ( i = 0; i < nr_pfns; i++ )
{
- ASSERT(!(pg[i].count_info & ~PGC_extra));
+ ASSERT(!(pg[i].count_info & ~(PGC_extra | PGC_reserved)));
I think this change belongs to the previous patch.
if ( pg[i].count_info & PGC_extra )
extra_pages++;
}
@@ -2439,6 +2439,9 @@ int assign_pages(
}
}
+ if ( pg[0].count_info & PGC_reserved )
+ d->reserved_pages += nr_pfns;
reserved_pages doesn't seem to be ever read or decremented. So why do
you need it?
+
if ( !(memflags & MEMF_no_refcount) &&
unlikely(domain_adjust_tot_pages(d, nr_pfns) == nr_pfns) )
get_knownalive_domain(d);
@@ -2452,7 +2455,7 @@ int assign_pages(
page_set_reserved_owner(&pg[i], d);
smp_wmb(); /* Domain pointer must be visible before updating refcnt.
*/
pg[i].count_info =
- (pg[i].count_info & PGC_extra) | PGC_allocated | 1;
+ (pg[i].count_info & (PGC_extra | PGC_reserved)) | PGC_allocated |
1;
Same here.
page_list_add_tail(&pg[i], page_to_list(d, &pg[i]));
}
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 3982167144..b6333ed8bb 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -368,6 +368,7 @@ struct domain
struct page_list_head page_list; /* linked list */
struct page_list_head extra_page_list; /* linked list (size extra_pages)
*/
struct page_list_head xenpage_list; /* linked list (size xenheap_pages) */
+ struct page_list_head reserved_page_list; /* linked list (size reserved
pages) */
/*
* This field should only be directly accessed by
domain_adjust_tot_pages()
@@ -379,6 +380,7 @@ struct domain
unsigned int outstanding_pages; /* pages claimed but not possessed */
unsigned int max_pages; /* maximum value for
domain_tot_pages() */
unsigned int extra_pages; /* pages not included in
domain_tot_pages() */
+ unsigned int reserved_pages; /* pages of static memory */
atomic_t shr_pages; /* shared pages */
atomic_t paged_pages; /* paged-out pages */
@@ -588,6 +590,9 @@ static inline struct page_list_head *page_to_list(
if ( pg->count_info & PGC_extra )
return &d->extra_page_list;
+ if ( pg->count_info & PGC_reserved )
+ return &d->reserved_page_list;
+
return &d->page_list;
}
Cheers,
--
Julien Grall