From: Andrew Morton <akpm@linux-foundation.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] thp: define HPAGE_PMD_* constans as BUILD_BUG() if !THP
Date: Mon, 17 Jun 2013 15:33:22 -0700 [thread overview]
Message-ID: <20130617153322.f3cecaa54aacd465fedb7c36@linux-foundation.org> (raw)
In-Reply-To: <20130617222703.D8C4AE0090@blue.fi.intel.com>
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.
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WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] thp: define HPAGE_PMD_* constans as BUILD_BUG() if !THP
Date: Mon, 17 Jun 2013 15:33:22 -0700 [thread overview]
Message-ID: <20130617153322.f3cecaa54aacd465fedb7c36@linux-foundation.org> (raw)
In-Reply-To: <20130617222703.D8C4AE0090@blue.fi.intel.com>
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.
next prev parent reply other threads:[~2013-06-17 22:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-17 22:05 [PATCH] thp: define HPAGE_PMD_* constans as BUILD_BUG() if !THP Kirill A. Shutemov
2013-06-17 22:05 ` Kirill A. Shutemov
2013-06-17 22:14 ` Andrew Morton
2013-06-17 22:14 ` Andrew Morton
2013-06-17 22:27 ` Kirill A. Shutemov
2013-06-17 22:27 ` Kirill A. Shutemov
2013-06-17 22:33 ` Andrew Morton [this message]
2013-06-17 22:33 ` Andrew Morton
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