[PATCH 08/10] xen/arm: introduce reserved_page_list

[Penny Zheng <penny.zheng@arm.com>]

Since page_list under struct domain refers to linked pages as gueast RAM
allocated from heap, it should not include reserved pages of static memory.

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.zheng@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)));
             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;
+
     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;
         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;
 }
 
-- 
2.25.1