From: Andrew Morton <akpm@linux-foundation.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: aarcange@redhat.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, paulus@samba.org,
linuxppc-dev@lists.ozlabs.org, kirill.shutemov@linux.intel.com
Subject: Re: [PATCH V2 1/2] mm/thp: Split out pmd collpase flush into a seperate functions
Date: Fri, 8 May 2015 15:24:28 -0700 [thread overview]
Message-ID: <20150508152428.4326eaaae99b74fa53c96f23@linux-foundation.org> (raw)
In-Reply-To: <1430983408-24924-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
On Thu, 7 May 2015 12:53:27 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
> After this patch pmdp_* functions operate only on hugepage pte,
> and not on regular pmd_t values pointing to page table.
>
The patch looks like a pretty safe no-op for non-powerpc?
> --- a/arch/powerpc/include/asm/pgtable-ppc64.h
> +++ b/arch/powerpc/include/asm/pgtable-ppc64.h
> @@ -576,6 +576,10 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long addr,
> extern void pmdp_splitting_flush(struct vm_area_struct *vma,
> unsigned long address, pmd_t *pmdp);
>
> +#define __HAVE_ARCH_PMDP_COLLAPSE_FLUSH
> +extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp);
> +
The fashionable way of doing this is
extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp);
#define pmdp_collapse_flush pmdp_collapse_flush
then, elsewhere,
#ifndef pmdp_collapse_flush
static inline pmd_t pmdp_collapse_flush(...) {}
#define pmdp_collapse_flush pmdp_collapse_flush
#endif
It avoids introducing a second (ugly) symbol into the kernel.
next prev parent reply other threads:[~2015-05-08 22:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-07 7:23 [PATCH V2 1/2] mm/thp: Split out pmd collpase flush into a seperate functions Aneesh Kumar K.V
2015-05-07 7:23 ` [PATCH V2 2/2] powerpc/thp: Serialize pmd clear against a linux page table walk Aneesh Kumar K.V
2015-05-08 22:21 ` Andrew Morton
2015-05-11 6:30 ` Aneesh Kumar K.V
2015-05-07 9:20 ` [PATCH V2 1/2] mm/thp: Split out pmd collpase flush into a seperate functions Kirill A. Shutemov
2015-05-07 11:18 ` Aneesh Kumar K.V
2015-05-08 22:24 ` Andrew Morton [this message]
2015-05-11 6:32 ` Aneesh Kumar K.V
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