Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756998Ab0KRMv3 (ORCPT ); Thu, 18 Nov 2010 07:51:29 -0500 Received: from gir.skynet.ie ([193.1.99.77]:46524 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756214Ab0KRMv2 (ORCPT ); Thu, 18 Nov 2010 07:51:28 -0500 Date: Thu, 18 Nov 2010 12:51:12 +0000 From: Mel Gorman To: Andrea Arcangeli Cc: linux-mm@kvack.org, Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org, Marcelo Tosatti , Adam Litke , Avi Kivity , Hugh Dickins , Rik van Riel , Dave Hansen , Benjamin Herrenschmidt , Ingo Molnar , Mike Travis , KAMEZAWA Hiroyuki , Christoph Lameter , Chris Wright , bpicco@redhat.com, KOSAKI Motohiro , Balbir Singh , "Michael S. Tsirkin" , Peter Zijlstra , Johannes Weiner , Daisuke Nishimura , Chris Mason , Borislav Petkov Subject: Re: [PATCH 16 of 66] special pmd_trans_* functions Message-ID: <20101118125112.GM8135@csn.ul.ie> References: <522a9ff792e43eb0ec6a.1288798071@v2.random> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <522a9ff792e43eb0ec6a.1288798071@v2.random> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3440 Lines: 96 On Wed, Nov 03, 2010 at 04:27:51PM +0100, Andrea Arcangeli wrote: > From: Andrea Arcangeli > > These returns 0 at compile time when the config option is disabled, to allow > gcc to eliminate the transparent hugepage function calls at compile time > without additional #ifdefs (only the export of those functions have to be > visible to gcc but they won't be required at link time and huge_memory.o can be > not built at all). > > _PAGE_BIT_UNUSED1 is never used for pmd, only on pte. > > Signed-off-by: Andrea Arcangeli > Acked-by: Rik van Riel > --- > > diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h > --- a/arch/x86/include/asm/pgtable_64.h > +++ b/arch/x86/include/asm/pgtable_64.h > @@ -168,6 +168,19 @@ extern void cleanup_highmap(void); > #define kc_offset_to_vaddr(o) ((o) | ~__VIRTUAL_MASK) > > #define __HAVE_ARCH_PTE_SAME > + > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +static inline int pmd_trans_splitting(pmd_t pmd) > +{ > + return pmd_val(pmd) & _PAGE_SPLITTING; > +} > + > +static inline int pmd_trans_huge(pmd_t pmd) > +{ > + return pmd_val(pmd) & _PAGE_PSE; > +} > +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ > + > #endif /* !__ASSEMBLY__ */ > > #endif /* _ASM_X86_PGTABLE_64_H */ > diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h > --- a/arch/x86/include/asm/pgtable_types.h > +++ b/arch/x86/include/asm/pgtable_types.h > @@ -22,6 +22,7 @@ > #define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */ > #define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1 > #define _PAGE_BIT_CPA_TEST _PAGE_BIT_UNUSED1 > +#define _PAGE_BIT_SPLITTING _PAGE_BIT_UNUSED1 /* only valid on a PSE pmd */ > #define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */ > > /* If _PAGE_BIT_PRESENT is clear, we use these: */ > @@ -45,6 +46,7 @@ > #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE) > #define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL) > #define _PAGE_CPA_TEST (_AT(pteval_t, 1) << _PAGE_BIT_CPA_TEST) > +#define _PAGE_SPLITTING (_AT(pteval_t, 1) << _PAGE_BIT_SPLITTING) > #define __HAVE_ARCH_PTE_SPECIAL > > #ifdef CONFIG_KMEMCHECK > diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h > --- a/include/asm-generic/pgtable.h > +++ b/include/asm-generic/pgtable.h > @@ -348,6 +348,11 @@ extern void untrack_pfn_vma(struct vm_ar > unsigned long size); > #endif > > +#ifndef CONFIG_TRANSPARENT_HUGEPAGE > +#define pmd_trans_huge(pmd) 0 > +#define pmd_trans_splitting(pmd) 0 > +#endif > + Usually it is insisted upon that this looks like static inline int pmd_trans_huge(pmd) { return 0; } I understand it's to avoid any possibility of side-effets though to have type checking and I am 99% certain the compiler still does the right thing. Still, with no obvious side-effects here; Acked-by: Mel Gorman > #endif /* !__ASSEMBLY__ */ > > #endif /* _ASM_GENERIC_PGTABLE_H */ > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/