sugar/linux
1
0
Fork 0
Code Activity

thp: alter compound get_page/put_page

Browse Source 
Alter compound get_page/put_page to keep references on subpages too, in
order to allow __split_huge_page_refcount to split an hugepage even while
subpages have been pinned by one of the get_user_pages() variants.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrea Arcangeli
2011-01-13 15:46:32 -08:00
committed by Linus Torvalds
parent e9da73d677
commit 9180706344
4 changed files with 129 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
arch/powerpc/mm/gup.c
View File

@@ -16,6 +16,16 @@
#ifdef __HAVE_ARCH_PTE_SPECIAL
static inline void get_huge_page_tail(struct page *page)
{
/*
* __split_huge_page_refcount() cannot run
* from under us.
*/
VM_BUG_ON(atomic_read(&page->_count) < 0);
atomic_inc(&page->_count);
}
/*
* The performance critical leaf functions are made noinline otherwise gcc
* inlines everything into a single function which results in too much
@@ -47,6 +57,8 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
put_page(page);
return 0;
}
if (PageTail(page))
get_huge_page_tail(page);
pages[*nr] = page;
(*nr)++;

12
arch/x86/mm/gup.c
View File

@@ -105,6 +105,16 @@ static inline void get_head_page_multiple(struct page *page, int nr)
atomic_add(nr, &page->_count);
}
static inline void get_huge_page_tail(struct page *page)
{
/*
* __split_huge_page_refcount() cannot run
* from under us.
*/
VM_BUG_ON(atomic_read(&page->_count) < 0);
atomic_inc(&page->_count);
}
static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
@@ -128,6 +138,8 @@ static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr,
do {
VM_BUG_ON(compound_head(page) != head);
pages[*nr] = page;
if (PageTail(page))
get_huge_page_tail(page);
(*nr)++;
page++;
refs++;