[PATCH V4 10/15] xen/page_alloc: vmap heap nodes when they are outside the direct map

[Elias El Yandouzi <eliasely@xxxxxxxxxx>]

From: Hongyan Xia <hongyxia@xxxxxxxxxx>

When we do not have a direct map, archs_mfn_in_direct_map() will always
return false, thus init_node_heap() will allocate xenheap pages from an
existing node for the metadata of a new node. This means that the
metadata of a new node is in a different node, slowing down heap
allocation.

Since we now have early vmap, vmap the metadata locally in the new node.

Signed-off-by: Hongyan Xia <hongyxia@xxxxxxxxxx>
Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
Signed-off-by: Elias El Yandouzi <eliasely@xxxxxxxxxx>

----

    Changes in v4:
        * Change type of the parameters to paddr_t
        * Use clear_domain_page() instead of open-coding it

    Changes in v2:
        * vmap_contig_pages() was renamed to vmap_contig()
        * Fix indentation and coding style

    Changes from Hongyan's version:
        * arch_mfn_in_direct_map() was renamed to
          arch_mfns_in_direct_map()
        * Use vmap_contig_pages() rather than __vmap(...).
        * Add missing include (xen/vmap.h) so it compiles on Arm

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 2cef521ad85a..62cdeb5013a3 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -137,6 +137,7 @@
 #include <xen/sections.h>
 #include <xen/softirq.h>
 #include <xen/spinlock.h>
+#include <xen/vmap.h>
 
 #include <asm/flushtlb.h>
 #include <asm/page.h>
@@ -606,22 +607,32 @@ static unsigned long init_node_heap(int node, unsigned 
long mfn,
         needed = 0;
     }
     else if ( *use_tail && nr >= needed &&
-              arch_mfns_in_directmap(mfn + nr - needed, needed) &&
               (!xenheap_bits ||
                !((mfn + nr - 1) >> (xenheap_bits - PAGE_SHIFT))) )
     {
-        _heap[node] = mfn_to_virt(mfn + nr - needed);
-        avail[node] = mfn_to_virt(mfn + nr - 1) +
-                      PAGE_SIZE - sizeof(**avail) * NR_ZONES;
+        if ( arch_mfns_in_directmap(mfn + nr - needed, needed) )
+            _heap[node] = mfn_to_virt(mfn + nr - needed);
+        else
+            _heap[node] = vmap_contig(_mfn(mfn + nr - needed), needed);
+
+        BUG_ON(!_heap[node]);
+        avail[node] = (void *)(_heap[node]) + (needed << PAGE_SHIFT) -
+                        sizeof(**avail) * NR_ZONES;
+
     }
     else if ( nr >= needed &&
-              arch_mfns_in_directmap(mfn, needed) &&
               (!xenheap_bits ||
-               !((mfn + needed - 1) >> (xenheap_bits - PAGE_SHIFT))) )
+              !((mfn + needed - 1) >> (xenheap_bits - PAGE_SHIFT))) )
     {
-        _heap[node] = mfn_to_virt(mfn);
-        avail[node] = mfn_to_virt(mfn + needed - 1) +
-                      PAGE_SIZE - sizeof(**avail) * NR_ZONES;
+        if ( arch_mfns_in_directmap(mfn + nr - needed, needed) )
+            _heap[node] = mfn_to_virt(mfn + nr - needed);
+        else
+            _heap[node] = vmap_contig(_mfn(mfn + nr - needed), needed);
+
+        BUG_ON(!_heap[node]);
+        avail[node] = (void *)(_heap[node]) + (needed << PAGE_SHIFT) -
+                        sizeof(**avail) * NR_ZONES;
+
         *use_tail = false;
     }
     else if ( get_order_from_bytes(sizeof(**_heap)) ==
-- 
2.40.1