On Fri, 2012-06-08 at 14:31 -0500, Christoph Lameter wrote: > On Fri, 8 Jun 2012, Glauber Costa wrote: > > > */ > > #define __GFP_NOTRACK_FALSE_POSITIVE (__GFP_NOTRACK) > > > > -#define __GFP_BITS_SHIFT 25 /* Room for N __GFP_FOO bits */ > > +#define __GFP_BITS_SHIFT 26 /* Room for N __GFP_FOO bits */ > > #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1)) > > Please make this conditional on CONFIG_MEMCG or so. The bit can be useful > in particular on 32 bit architectures. I really don't think that's at all a good idea. It's asking for trouble when we don't spot we have a flag overlap. It also means that we're trusting the reuser to know that their use case can never clash with CONFIG_MEMGC and I can't think of any configuration where this is possible currently. I think making the flag define of __GFP_SLABMEMCG conditional might be a reasonable idea so we get a compile failure if anyone tries to use it when !CONFIG_MEMCG. James -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>