1 files changed, 19 insertions, 11 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index c79882ecb51..161333785f6 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -162,33 +162,41 @@ typedef int (*xfs_buf_bdstrat_t)(struct xfs_buf *);
 #define XB_PAGES        2
 
 typedef struct xfs_buf {
+        /*
+         * first cacheline holds all the fields needed for an uncontended cache
+         * hit to be fully processed. The semaphore straddles the cacheline
+         * boundary, but the counter and lock sits on the first cacheline,
+         * which is the only bit that is touched if we hit the semaphore
+         * fast-path on locking.
+         */
+        struct rb_node          b_rbnode;       /* rbtree node */
+        xfs_off_t               b_file_offset;  /* offset in file */
+        size_t                  b_buffer_length;/* size of buffer in bytes */
+        atomic_t                b_hold;         /* reference count */
+        xfs_buf_flags_t         b_flags;        /* status flags */
         struct semaphore        b_sema;         /* semaphore for lockables */
-        unsigned long           b_queuetime;    /* time buffer was queued */
-        atomic_t                b_pin_count;    /* pin count */
+
         wait_queue_head_t       b_waiters;      /* unpin waiters */
         struct list_head        b_list;
-        xfs_buf_flags_t         b_flags;        /* status flags */
-        struct rb_node          b_rbnode;       /* rbtree node */
         struct xfs_perag        *b_pag;         /* contains rbtree root */
         xfs_buftarg_t           *b_target;      /* buffer target (device) */
-        atomic_t                b_hold;         /* reference count */
         xfs_daddr_t             b_bn;           /* block number for I/O */
-        xfs_off_t               b_file_offset;  /* offset in file */
-        size_t                  b_buffer_length;/* size of buffer in bytes */
         size_t                  b_count_desired;/* desired transfer size */
         void                    *b_addr;        /* virtual address of buffer */
         struct work_struct      b_iodone_work;
-        atomic_t                b_io_remaining; /* #outstanding I/O requests */
         xfs_buf_iodone_t        b_iodone;       /* I/O completion function */
         xfs_buf_relse_t         b_relse;        /* releasing function */
         struct completion       b_iowait;       /* queue for I/O waiters */
         void                    *b_fspriv;
         void                    *b_fspriv2;
-        unsigned short          b_error;        /* error code on I/O */
-        unsigned int            b_page_count;   /* size of page array */
-        unsigned int            b_offset;       /* page offset in first page */
         struct page             **b_pages;      /* array of page pointers */
         struct page             *b_page_array[XB_PAGES]; /* inline pages */
+        unsigned long           b_queuetime;    /* time buffer was queued */
+        atomic_t                b_pin_count;    /* pin count */
+        atomic_t                b_io_remaining; /* #outstanding I/O requests */
+        unsigned int            b_page_count;   /* size of page array */
+        unsigned int            b_offset;       /* page offset in first page */
+        unsigned short          b_error;        /* error code on I/O */
 #ifdef XFS_BUF_LOCK_TRACKING
         int                     b_last_holder;
 #endif