mm: keep PGC_extra pages on a separate list

This patch adds a new page_list_head into struct domain to hold PGC_extra
pages. This avoids them getting confused with 'normal' domheap pages where
the domain's page_list is walked.

A new dump loop is also added to dump_pageframe_info() to unconditionally
dump the 'extra page list'.

Signed-off-by: Paul Durrant <paul@xen.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Julien Grall <julien@xen.org>

xen/arch/x86/domain.c

@@ -251,12 +251,21 @@ void dump_pageframe_info(struct domain *d)
         p2m_pod_dump_data(d);
 
     spin_lock(&d->page_alloc_lock);
+
     page_list_for_each ( page, &d->xenpage_list )
     {
         printk("    XenPage %p: caf=%08lx, taf=%" PRtype_info "\n",
                _p(mfn_x(page_to_mfn(page))),
                page->count_info, page->u.inuse.type_info);
     }
+
+    page_list_for_each ( page, &d->extra_page_list )
+    {
+        printk("    ExtraPage %p: caf=%08lx, taf=%" PRtype_info "\n",
+               _p(mfn_x(page_to_mfn(page))),
+               page->count_info, page->u.inuse.type_info);
+    }
+
     spin_unlock(&d->page_alloc_lock);
 }
 

xen/common/domain.c

@@ -403,6 +403,7 @@ struct domain *domain_create(domid_t domid,
     spin_lock_init_prof(d, page_alloc_lock);
     spin_lock_init(&d->hypercall_deadlock_mutex);
     INIT_PAGE_LIST_HEAD(&d->page_list);
+    INIT_PAGE_LIST_HEAD(&d->extra_page_list);
     INIT_PAGE_LIST_HEAD(&d->xenpage_list);
 
     spin_lock_init(&d->node_affinity_lock);

xen/common/page_alloc.c

@@ -2314,7 +2314,7 @@ int assign_pages(
         smp_wmb(); /* Domain pointer must be visible before updating refcnt. */
         pg[i].count_info =
             (pg[i].count_info & PGC_extra) | PGC_allocated | 1;
-        page_list_add_tail(&pg[i], &d->page_list);
+        page_list_add_tail(&pg[i], page_to_list(d, &pg[i]));
     }
 
  out:

xen/include/asm-x86/mm.h

@@ -629,10 +629,8 @@ typedef struct mm_rwlock {
     const char        *locker_function; /* func that took it */
 } mm_rwlock_t;
 
-#define arch_free_heap_page(d, pg)                                      \
-    page_list_del2(pg, is_xen_heap_page(pg) ?                           \
-                       &(d)->xenpage_list : &(d)->page_list,            \
-                   &(d)->arch.relmem_list)
+#define arch_free_heap_page(d, pg) \
+    page_list_del2(pg, page_to_list(d, pg), &(d)->arch.relmem_list)
 
 extern const char zero_page[];
 

xen/include/xen/mm.h

@@ -583,9 +583,8 @@ static inline unsigned int get_order_from_pages(unsigned long nr_pages)
 void scrub_one_page(struct page_info *);
 
 #ifndef arch_free_heap_page
-#define arch_free_heap_page(d, pg)                      \
-    page_list_del(pg, is_xen_heap_page(pg) ?            \
-                      &(d)->xenpage_list : &(d)->page_list)
+#define arch_free_heap_page(d, pg) \
+    page_list_del(pg, page_to_list(d, pg))
 #endif
 
 int xenmem_add_to_physmap_one(struct domain *d, unsigned int space,

xen/include/xen/sched.h

@@ -329,6 +329,7 @@ struct domain
 
     spinlock_t       page_alloc_lock; /* protects all the following fields  */
     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) */
 
     /*
@@ -512,6 +513,18 @@ struct domain
 #endif
 };
 
+static inline struct page_list_head *page_to_list(
+    struct domain *d, const struct page_info *pg)
+{
+    if ( is_xen_heap_page(pg) )
+        return &d->xenpage_list;
+
+    if ( pg->count_info & PGC_extra )
+        return &d->extra_page_list;
+
+    return &d->page_list;
+}
+
 /* Return number of pages currently posessed by the domain */
 static inline unsigned int domain_tot_pages(const struct domain *d)
 {