PRSHIFT           113 fs/xfs/linux-2.6/xfs_buf.c #define PRSHIFT		(PAGE_CACHE_SHIFT - 5)	/* (32 == 1<<5) */
PRSHIFT           115 fs/xfs/linux-2.6/xfs_buf.c #define PRSHIFT		(PAGE_CACHE_SHIFT - 6)	/* (64 == 1<<6) */