Changeset 482f968 in mainline for kernel/generic/src/mm/frame.c

Timestamp:

2018-10-31T16:48:51Z (7 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

91a8f83, bab75df6

Parents:

37781819

Message:

Make FRAME_HIGHMEM fall back to low memory on failure.

Which is what existing users of it are doing, and there is no reason
not to as far as I can see.

Also make sure calls to frame_alloc all have either FRAME_LOWMEM or
FRAME_HIGHMEM explicitly set, as appropriate.

File:

• kernel/generic/src/mm/frame.c (modified) (4 diffs)

kernel/generic/src/mm/frame.c

@@ -815 +815 @@
 }
 
+static size_t try_find_zone(size_t count, bool lowmem,
+    pfn_t frame_constraint, size_t hint)
+{
+        if (!lowmem) {
+                size_t znum = find_free_zone(count,
+                    ZONE_HIGHMEM | ZONE_AVAILABLE, frame_constraint, hint);
+                if (znum != (size_t) -1)
+                        return znum;
+        }
+
+        return find_free_zone(count, ZONE_LOWMEM | ZONE_AVAILABLE,
+            frame_constraint, hint);
+}
+
 /** Allocate frames of physical memory.
  *
@@ -843 +857 @@
         irq_spinlock_lock(&zones.lock, true);
 
+        // TODO: Print diagnostic if neither is explicitly specified.
+        bool lowmem = (flags & FRAME_LOWMEM) || !(flags & FRAME_HIGHMEM);
+
         /*
          * First, find suitable frame zone.
          */
-        size_t znum = find_free_zone(count, FRAME_TO_ZONE_FLAGS(flags),
-            frame_constraint, hint);
+        size_t znum = try_find_zone(count, lowmem, frame_constraint, hint);
 
         /*
@@ -859 +875 @@
 
                 if (freed > 0)
-                        znum = find_free_zone(count, FRAME_TO_ZONE_FLAGS(flags),
+                        znum = try_find_zone(count, lowmem,
                             frame_constraint, hint);
 
@@ -868 +884 @@
 
                         if (freed > 0)
-                                znum = find_free_zone(count, FRAME_TO_ZONE_FLAGS(flags),
+                                znum = try_find_zone(count, lowmem,
                                     frame_constraint, hint);
                 }