revert "s390/mm: make hugepages_supported a boot time decision"

Heiko noticed that the current check for hugepage support on s390 is a
little bit too harsh as systems which do not support will crash.

The reason is that pageblock_order can now get negative when we set
HPAGE_SHIFT to 0.  To avoid all this and to avoid opening another can of
worms with enabling HUGETLB_PAGE_SIZE_VARIABLE I think it would be best
to simply allow architectures to define their own hugepages_supported().

Revert bea41197ea ("s390/mm: make hugepages_supported a boot time
decision") in preparation.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dominik Dingel 2015-07-17 16:23:34 -07:00 committed by Linus Torvalds
parent ad4f99e888
commit 41318bfe2a
3 changed files with 4 additions and 8 deletions

View File

@ -17,10 +17,7 @@
#define PAGE_DEFAULT_ACC 0
#define PAGE_DEFAULT_KEY (PAGE_DEFAULT_ACC << 4)
#include <asm/setup.h>
#ifndef __ASSEMBLY__
extern unsigned int HPAGE_SHIFT;
#define HPAGE_SHIFT 20
#define HPAGE_SIZE (1UL << HPAGE_SHIFT)
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
@ -30,6 +27,9 @@ extern unsigned int HPAGE_SHIFT;
#define ARCH_HAS_PREPARE_HUGEPAGE
#define ARCH_HAS_HUGEPAGE_CLEAR_FLUSH
#include <asm/setup.h>
#ifndef __ASSEMBLY__
static inline void storage_key_init_range(unsigned long start, unsigned long end)
{
#if PAGE_DEFAULT_KEY

View File

@ -885,8 +885,6 @@ void __init setup_arch(char **cmdline_p)
*/
setup_hwcaps();
HPAGE_SHIFT = MACHINE_HAS_HPAGE ? 20 : 0;
/*
* Create kernel page tables and switch to virtual addressing.
*/

View File

@ -31,8 +31,6 @@
#define ALLOC_ORDER 2
#define FRAG_MASK 0x03
unsigned int HPAGE_SHIFT;
unsigned long *crst_table_alloc(struct mm_struct *mm)
{
struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);