2012-08-22 03:02:37

by Jovi Zhang

Subject: [PATCH] MIPS/mm: add compound tail page _mapcount when mapped

>From 3dc19ea2b535719d0b4177f17bbbff9cbf257b23 Mon Sep 17 00:00:00 2001
From: Jovi Zhang <[email protected]>
Date: Wed, 22 Aug 2012 10:34:08 +0800
Subject: [PATCH] MIPS/mm: add compound tail page _mapcount when mapped

see commit b6999b191 which target for x86 mm/gup, let it align with
mips architecture.

Quote from commit b6999b191:
"If compound pages are used and the page is a
tail page, gup_huge_pmd() increases _mapcount to record tail page are
mapped while gup_huge_pud does not do that."

Signed-off-by: Jovi Zhang <[email protected]>
Cc: Youquan Song <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: <[email protected]>
---
arch/mips/mm/gup.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/mips/mm/gup.c b/arch/mips/mm/gup.c
index 33aadbc..dcfd573 100644
--- a/arch/mips/mm/gup.c
+++ b/arch/mips/mm/gup.c
@@ -152,6 +152,8 @@ static int gup_huge_pud(pud_t pud, unsigned long
addr, unsigned long end,
do {
VM_BUG_ON(compound_head(page) != head);
pages[*nr] = page;
+ if (PageTail(page))
+ get_huge_page_tail(page);
(*nr)++;
page++;
refs++;
--
1.7.9.7

2012-08-24 13:23:34

by Ralf Baechle

Subject: Re: [PATCH] MIPS/mm: add compound tail page _mapcount when mapped

On Wed, Aug 22, 2012 at 11:02:34AM +0800, Jovi Zhang wrote:

> see commit b6999b191 which target for x86 mm/gup, let it align with
> mips architecture.
>
> Quote from commit b6999b191:
> "If compound pages are used and the page is a
> tail page, gup_huge_pmd() increases _mapcount to record tail page are
> mapped while gup_huge_pud does not do that."

Thanks, applied and also acked' for -stable.

Note the patch got linewrapped along the way but it's trivial enough to be
fixed up.

Ralf