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s390, thp: remove infrastructure for handling splitting PMDs

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With new refcounting we don't need to mark PMDs splitting.  Let's drop
code to handle this.

pmdp_splitting_flush() is not needed too: on splitting PMD we will do
pmdp_clear_flush() + set_pte_at().  pmdp_clear_flush() will do IPI as
needed for fast_gup.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2016-01-15 16:53:24 -08:00 committed by Linus Torvalds
parent 7aa9a23c69
commit fecffad254
3 changed files with 2 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
arch/s390/include/asm/pgtable.h
View File

@ -286,7 +286,6 @@ static inline int is_module_addr(void *addr)
#define _SEGMENT_ENTRY_DIRTY 0x2000 /* SW segment dirty bit */
#define _SEGMENT_ENTRY_YOUNG 0x1000 /* SW segment young bit */
#define _SEGMENT_ENTRY_SPLIT 0x0800 /* THP splitting bit */
#define _SEGMENT_ENTRY_LARGE 0x0400 /* STE-format control, large page */
#define _SEGMENT_ENTRY_READ 0x0002 /* SW segment read bit */
#define _SEGMENT_ENTRY_WRITE 0x0001 /* SW segment write bit */
@ -318,8 +317,6 @@ static inline int is_module_addr(void *addr)
* SW-bits: y young, d dirty, r read, w write
*/
#define _SEGMENT_ENTRY_SPLIT_BIT 11 /* THP splitting bit number */
/* Page status table bits for virtualization */
#define PGSTE_ACC_BITS 0xf000000000000000UL
#define PGSTE_FP_BIT 0x0800000000000000UL
@ -523,10 +520,6 @@ static inline int pmd_bad(pmd_t pmd)
return (pmd_val(pmd) & ~_SEGMENT_ENTRY_BITS) != 0;
}
#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
extern void pmdp_splitting_flush(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmdp);
#define __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
extern int pmdp_set_access_flags(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp,
@ -1424,8 +1417,7 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
if (pmd_large(pmd)) {
pmd_val(pmd) &= _SEGMENT_ENTRY_ORIGIN_LARGE |
_SEGMENT_ENTRY_DIRTY | _SEGMENT_ENTRY_YOUNG |
_SEGMENT_ENTRY_LARGE | _SEGMENT_ENTRY_SPLIT |
_SEGMENT_ENTRY_SOFT_DIRTY;
_SEGMENT_ENTRY_LARGE | _SEGMENT_ENTRY_SOFT_DIRTY;
pmd_val(pmd) |= massage_pgprot_pmd(newprot);
if (!(pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY))
pmd_val(pmd) |= _SEGMENT_ENTRY_PROTECT;
@ -1533,12 +1525,6 @@ extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
#define __HAVE_ARCH_PGTABLE_WITHDRAW
extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
static inline int pmd_trans_splitting(pmd_t pmd)
{
return (pmd_val(pmd) & _SEGMENT_ENTRY_LARGE) &&
(pmd_val(pmd) & _SEGMENT_ENTRY_SPLIT);
}
static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t entry)
{

11
arch/s390/mm/gup.c
View File

@ -105,16 +105,7 @@ static inline int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr,
pmd = *pmdp;
barrier();
next = pmd_addr_end(addr, end);
/*
* The pmd_trans_splitting() check below explains why
* pmdp_splitting_flush() has to serialize with
* smp_call_function() against our disabled IRQs, to stop
* this gup-fast code from running while we set the
* splitting bit in the pmd. Returning zero will take
* the slow path that will call wait_split_huge_page()
* if the pmd is still in splitting state.
*/
if (pmd_none(pmd) || pmd_trans_splitting(pmd))
if (pmd_none(pmd))
return 0;
if (unlikely(pmd_large(pmd))) {
/*

16
arch/s390/mm/pgtable.c
View File

@ -1305,22 +1305,6 @@ int pmdp_set_access_flags(struct vm_area_struct *vma,
return 1;
}
static void pmdp_splitting_flush_sync(void *arg)
{
/* Simply deliver the interrupt */
}
void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
if (!test_and_set_bit(_SEGMENT_ENTRY_SPLIT_BIT,
(unsigned long *) pmdp)) {
/* need to serialize against gup-fast (IRQ disabled) */
smp_call_function(pmdp_splitting_flush_sync, NULL, 1);
}
}
void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable)
{