Changeset e5a015b in mainline for kernel/generic/include/mm/frame.h

Timestamp:

2011-04-16T20:45:36Z (13 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

a7dbd49

Parents:

b2fb47f (diff), 9e953bda (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge the memory reservation feature (Phase 1) from
lp:~jakub/helenos/mm.

This merge makes the testcase from ticket #114 non-reproducible. The
testcase is now available as tester's malloc2 test. It also seems to me
that this merge makes it harder for the system to run out of memory
during kconsole 'test *' and 'tester *', even though I did see several
hangs already with this feature in place. See below for what is still
missing to make the hangs even less probable or even impossible.

In Phase 1, I am targeting just the low-hanging fruits. In particular,
only anonymous and ELF backend pages are reserved physical memory at
time of as_area_create() and as_area_resize(). Memory is unreserved on
as_area_destroy(). In all other cases, memory is reserved at the same
time as it is allocated, making those calls subject to infinite
blocking if FRAME_ATOMIC is not used.

Possible sources of memory overcommit not addressed in this merge:

• As mentioned above, only backend pages are reserved; pages for supporting structures such as B+tree nodes, TTEs are not reserved or handled otherwise. Kernel heap allocator fragmentation is not included in the reservations either.
• The initial amount of reservable memory is fed from zone_construct(). Zone merging is not taken into account, which can make the reservable memory tracking inaccurate.

File:

• kernel/generic/include/mm/frame.h (modified) (4 diffs)

kernel/generic/include/mm/frame.h

@@ -62 +62 @@
 
 /** Convert the frame address to kernel VA. */
-#define FRAME_KA          0x01
+#define FRAME_KA          0x1
 /** Do not panic and do not sleep on failure. */
-#define FRAME_ATOMIC      0x02
+#define FRAME_ATOMIC      0x2
 /** Do not start reclaiming when no free memory. */
-#define FRAME_NO_RECLAIM  0x04
+#define FRAME_NO_RECLAIM  0x4
+/** Do not reserve / unreserve memory. */
+#define FRAME_NO_RESERVE  0x8
 
 typedef uint8_t zone_flags_t;
 
 /** Available zone (free for allocation) */
-#define ZONE_AVAILABLE  0x00
+#define ZONE_AVAILABLE  0x0
 /** Zone is reserved (not available for allocation) */
-#define ZONE_RESERVED   0x08
+#define ZONE_RESERVED   0x8
 /** Zone is used by firmware (not available for allocation) */
 #define ZONE_FIRMWARE   0x10
@@ -85 +87 @@
         uint8_t buddy_order;  /**< Buddy system block order */
         link_t buddy_link;    /**< Link to the next free block inside
-                               one order */
+                                   one order */
         void *parent;         /**< If allocated by slab, this points there */
 } frame_t;
@@ -91 +93 @@
 typedef struct {
         pfn_t base;                    /**< Frame_no of the first frame
-                                        in the frames array */
+                                            in the frames array */
         size_t count;                  /**< Size of zone */
         size_t free_count;             /**< Number of free frame_t
-                                        structures */
+                                            structures */
         size_t busy_count;             /**< Number of busy frame_t
-                                        structures */
+                                            structures */
         zone_flags_t flags;            /**< Type of the zone */
         
         frame_t *frames;               /**< Array of frame_t structures
-                                        in this zone */
+                                            in this zone */
         buddy_system_t *buddy_system;  /**< Buddy system for the zone */
 } zone_t;
@@ -146 +148 @@
     ((~(((sysarg_t) -1) << (order)) & (index)) == 0)
 #define IS_BUDDY_LEFT_BLOCK(zone, frame) \
-    (((frame_index((zone), (frame)) >> (frame)->buddy_order) & 0x01) == 0)
+    (((frame_index((zone), (frame)) >> (frame)->buddy_order) & 0x1) == 0)
 #define IS_BUDDY_RIGHT_BLOCK(zone, frame) \
-    (((frame_index((zone), (frame)) >> (frame)->buddy_order) & 0x01) == 1)
+    (((frame_index((zone), (frame)) >> (frame)->buddy_order) & 0x1) == 1)
 #define IS_BUDDY_LEFT_BLOCK_ABS(zone, frame) \
-    (((frame_index_abs((zone), (frame)) >> (frame)->buddy_order) & 0x01) == 0)
+    (((frame_index_abs((zone), (frame)) >> (frame)->buddy_order) & 0x1) == 0)
 #define IS_BUDDY_RIGHT_BLOCK_ABS(zone, frame) \
-    (((frame_index_abs((zone), (frame)) >> (frame)->buddy_order) & 0x01) == 1)
-
-#define frame_alloc(order, flags) \
-    frame_alloc_generic(order, flags, NULL)
+    (((frame_index_abs((zone), (frame)) >> (frame)->buddy_order) & 0x1) == 1)
 
 extern void frame_init(void);
 extern void *frame_alloc_generic(uint8_t, frame_flags_t, size_t *);
+extern void *frame_alloc(uint8_t, frame_flags_t);
+extern void *frame_alloc_noreserve(uint8_t, frame_flags_t);
+extern void frame_free_generic(uintptr_t, frame_flags_t);
 extern void frame_free(uintptr_t);
+extern void frame_free_noreserve(uintptr_t);
 extern void frame_reference_add(pfn_t);
 
-extern size_t find_zone(pfn_t frame, size_t count, size_t hint);
+extern size_t find_zone(pfn_t, size_t, size_t);
 extern size_t zone_create(pfn_t, size_t, pfn_t, zone_flags_t);
 extern void *frame_get_parent(pfn_t, size_t);