Messages in this thread | | | Date | Mon, 17 Jun 2013 15:33:22 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] thp: define HPAGE_PMD_* constans as BUILD_BUG() if !THP |
| |
On Tue, 18 Jun 2013 01:27:03 +0300 (EEST) "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> wrote:
> > > #else /* CONFIG_TRANSPARENT_HUGEPAGE */ > > > +#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; }) > > > +#define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; }) > > > +#define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; }) > > > > > > > We've done this sort of thing before and it blew up. We do want to be > > able to use things like HPAGE_PMD_foo in global-var initialisers and > > definitions, but the problem is that BUILD_BUG() can't be used outside > > functions. > > I don't see how it's a blocker. For global variables, we will have to use > #ifdefs, but the approach is still useful for in-function code.
OK. Current mainline uses BUILD_BUG() here, so I guess the change won't break anything. Yet.
| |