On Fri, 24 Jul 2009 23:32:19 +0200 Jörn Engel <jo...@logfs.org> wrote:
> On Tue, 21 July 2009 01:46:41 +0200, Arnd Bergmann wrote: > > On Friday 17 July 2009, Greg Kroah-Hartman wrote: > > > @@ -43,7 +43,7 @@ typedef struct _RING_BUFFER { > > > // volatile u32 InterruptMask; > > > // Ring data starts here + RingDataStartOffset !!! DO NOT place > > > any fields below this !!! > > > u8 Buffer[0]; > > > -} STRUCT_PACKED RING_BUFFER; > > > +} __attribute__((packed)) RING_BUFFER; > > > > > > > The data structure is actually packed already, the attribute does not make > > it better > > and could be removed. We also have __packed as a shortcut for > > __attribute__((packed)). > > Honestly, I don't know how useful __packed really is. In a shared > kernel/userspace header, it is only defined for the kernel. > As I remember, gcc generates worse code for packed structures on many architectures since it may have to do byte fetchs/recombining to avoid unaligned accesses. -- _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/virtualization