修改bufferdesc大小，提升性能

src/include/access/double_write.h

@@ -322,7 +322,7 @@ inline bool dw_buf_valid_aio_finished(BufferDesc *buf_desc, uint32 buf_state)
         return true;
     }
 
-    return ((buf_state & BM_VALID) && ((buf_state & BM_DIRTY) || buf_desc->aio_in_progress));
+    return ((buf_state & BM_VALID) && ((buf_state & BM_DIRTY) || buf_desc->extra->aio_in_progress));
 }
 
 extern bool free_space_enough(int buf_id);

src/include/knl/knl_session.h

@@ -1846,7 +1846,7 @@ typedef struct knl_u_storage_context {
     /* Pointers to shared state */
     // struct BufferStrategyControl* StrategyControl;
     int NLocBuffer; /* until buffers are initialized */
-    struct BufferDesc* LocalBufferDescriptors;
+    union BufferDescPadded* LocalBufferDescriptors;
     Block* LocalBufferBlockPointers;
     int32* LocalRefCount;
     int nextFreeLocalBuf;

src/include/storage/buf/buf_internals.h

@@ -191,30 +191,35 @@ typedef struct {
  * We use this same struct for local buffer headers, but the lock fields
  * are not used and not all of the flag bits are useful either.
  */
-typedef struct BufferDesc {
-    BufferTag tag; /* ID of page contained in buffer */
-    /* state of the tag, containing flags, refcount and usagecount */
-    pg_atomic_uint32 state;
-
+typedef struct BufferDescExtra {
     /* Cached physical location for segment-page storage, used for xlog */
     uint8 seg_fileno;
     BlockNumber seg_blockno;
 
+    /* below fields are used for incremental checkpoint */
+    pg_atomic_uint64 rec_lsn;        /* recovery LSN */
+    volatile uint64 dirty_queue_loc; /* actual loc of dirty page queue */
+    bool encrypt; /* enable table's level data encryption */
+
+    volatile uint64 lsn_on_disk;
+
+    volatile bool aio_in_progress; /* indicate aio is in progress */
+} BufferDescExtra;
+
+typedef struct BufferDesc {
+    BufferTag tag; /* ID of page contained in buffer */
     int buf_id;    /* buffer's index number (from 0) */
 
+    /* state of the tag, containing flags, refcount and usagecount */
+    pg_atomic_uint32 state;
+
     ThreadId wait_backend_pid; /* backend PID of pin-count waiter */
 
     LWLock* io_in_progress_lock; /* to wait for I/O to complete */
     LWLock* content_lock;        /* to lock access to buffer contents */
 
-    /* below fields are used for incremental checkpoint */
-    pg_atomic_uint64 rec_lsn;        /* recovery LSN */
-    volatile uint64 dirty_queue_loc; /* actual loc of dirty page queue */
-    bool encrypt; /* enable table's level data encryption */
-    
-    volatile uint64 lsn_on_disk;
+    BufferDescExtra *extra;
 
-    volatile bool aio_in_progress; /* indicate aio is in progress */
 #ifdef USE_ASSERT_CHECKING
     volatile uint64 lsn_dirty;
 #endif
@@ -240,7 +245,8 @@ typedef struct BufferDesc {
  * platform with either 32 or 128 byte line sizes, it's good to align to
  * boundaries and avoid false sharing.
  */
-#define BUFFERDESC_PAD_TO_SIZE (SIZEOF_VOID_P == 8 ? 128 : 1)
+//#define BUFFERDESC_PAD_TO_SIZE (SIZEOF_VOID_P == 8 ? 128 : 1)
+#define BUFFERDESC_PAD_TO_SIZE (SIZEOF_VOID_P == 8 ? 64 : 1)
 
 typedef union BufferDescPadded {
     BufferDesc bufferdesc;
@@ -248,12 +254,12 @@ typedef union BufferDescPadded {
 } BufferDescPadded;
 
 #define GetBufferDescriptor(id) (&t_thrd.storage_cxt.BufferDescriptors[(id)].bufferdesc)
-#define GetLocalBufferDescriptor(id) (&t_thrd.storage_cxt.LocalBufferDescriptors[(id)])
+#define GetLocalBufferDescriptor(id) ((BufferDesc *)&u_sess->storage_cxt.LocalBufferDescriptors[(id)].bufferdesc)
 #define BufferDescriptorGetBuffer(bdesc) ((bdesc)->buf_id + 1)
 
 #define BufferGetBufferDescriptor(buffer)                          \
     (AssertMacro(BufferIsValid(buffer)), BufferIsLocal(buffer) ?   \
-        &u_sess->storage_cxt.LocalBufferDescriptors[-(buffer)-1] : \
+        (BufferDesc *)&u_sess->storage_cxt.LocalBufferDescriptors[-(buffer)-1].bufferdesc : \
         &t_thrd.storage_cxt.BufferDescriptors[(buffer)-1].bufferdesc)
 
 #define BufferDescriptorGetContentLock(bdesc) (((bdesc)->content_lock))