[ovs-dev] [PATCH] datapath-windows: Address memory allocation issues for OVS_BUFFER_CONTEXT

Anand Kumar kumaranand at vmware.com
Tue Mar 19 18:21:07 UTC 2019


With current implementation, when nbl pool is allocated, context size is
specified as 64 bytes, while the OVS_BUFFER_CONTEXT size is only 32 bytes.
Since context size is never changed, additional memory is not required.

This patch makes it simpler to allocate memory for OVS_BUFFER_CONTEXT so
that it is always aligned to MEMORY_ALLOCATION_ALIGNMENT.
This is acheived by updating "value" field in the context
structure, so that number of elements in array is always a multiple of
MEMORY_ALLOCATION_ALIGNMENT.

Also change the DEFAULT_CONTEXT_SIZE to accomodate OVS_BUFFER_CONTEXT size.

Signed-off-by: Anand Kumar <kumaranand at vmware.com>
---
 datapath-windows/ovsext/BufferMgmt.h | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/datapath-windows/ovsext/BufferMgmt.h b/datapath-windows/ovsext/BufferMgmt.h
index dcf310a..714ab3d 100644
--- a/datapath-windows/ovsext/BufferMgmt.h
+++ b/datapath-windows/ovsext/BufferMgmt.h
@@ -20,11 +20,8 @@
 #define MEM_ALIGN                       MEMORY_ALLOCATION_ALIGNMENT
 #define MEM_ALIGN_SIZE(_x)  ((MEM_ALIGN - 1 + (_x))/MEM_ALIGN * MEM_ALIGN)
 #define OVS_CTX_MAGIC                   0xabcd
-
-#define OVS_DEFAULT_NBL_CONTEXT_SIZE    MEM_ALIGN_SIZE(64)
-#define OVS_DEFAULT_NBL_CONTEXT_FILL    \
-      (OVS_DEFAULT_NBL_CONTEXT_SIZE - sizeof (OVS_BUFFER_CONTEXT))
-
+#define OVS_DEFAULT_NBL_CONTEXT_SIZE    sizeof(OVS_BUFFER_CONTEXT))
+#define OVS_DEFAULT_NBL_CONTEXT_FILL    0
 #define OVS_DEFAULT_DATA_SIZE           256
 #define OVS_DEFAULT_HEADROOM_SIZE       128
 #define OVS_FIX_NBL_DATA_SIZE    (OVS_DEFAULT_DATA_SIZE + OVS_DEFAULT_HEADROOM_SIZE)
@@ -49,7 +46,7 @@ enum {
 };
 
 typedef union _OVS_BUFFER_CONTEXT {
-    struct {
+    struct dummy {
         UINT16 magic;
         UINT16 flags;
         UINT32 srcPortNo;
@@ -61,7 +58,7 @@ typedef union _OVS_BUFFER_CONTEXT {
         UINT16 mru;
     };
 
-    UINT64 value[MEM_ALIGN_SIZE(32) >> 3];
+    CHAR value[MEM_ALIGN_SIZE(sizeof(struct dummy))];
 } OVS_BUFFER_CONTEXT, *POVS_BUFFER_CONTEXT;
 
 typedef struct _OVS_NBL_POOL {
-- 
2.9.3.windows.1



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