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arm, 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.

[arnd@arndb.de: fix unterminated ifdef in header file]
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: Vlastimil Babka <vbabka@suse.cz>
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: Arnd Bergmann <arnd@arndb.de>
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 16:53:14 -08:00 committed by Linus Torvalds
parent b7ed934a7c
commit 0ebd744615
3 changed files with 2 additions and 27 deletions
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9
arch/arm/include/asm/pgtable-3level.h
View file

@ -88,7 +88,6 @@
#define L_PMD_SECT_VALID (_AT(pmdval_t, 1) << 0)
#define L_PMD_SECT_DIRTY (_AT(pmdval_t, 1) << 55)
#define L_PMD_SECT_SPLITTING (_AT(pmdval_t, 1) << 56)
#define L_PMD_SECT_NONE (_AT(pmdval_t, 1) << 57)
#define L_PMD_SECT_RDONLY (_AT(pteval_t, 1) << 58)
@ -232,13 +231,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define pmd_trans_huge(pmd) (pmd_val(pmd) && !pmd_table(pmd))
#define pmd_trans_splitting(pmd) (pmd_isset((pmd), L_PMD_SECT_SPLITTING))
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp);
#endif
#endif
#define PMD_BIT_FUNC(fn,op) \
@ -246,7 +238,6 @@ static inline pmd_t pmd_##fn(pmd_t pmd) { pmd_val(pmd) op; return pmd; }
PMD_BIT_FUNC(wrprotect, |= L_PMD_SECT_RDONLY);
PMD_BIT_FUNC(mkold, &= ~PMD_SECT_AF);
PMD_BIT_FUNC(mksplitting, |= L_PMD_SECT_SPLITTING);
PMD_BIT_FUNC(mkwrite, &= ~L_PMD_SECT_RDONLY);
PMD_BIT_FUNC(mkdirty, |= L_PMD_SECT_DIRTY);
PMD_BIT_FUNC(mkyoung, |= PMD_SECT_AF);

5
arch/arm/lib/uaccess_with_memcpy.c
View file

@ -52,14 +52,13 @@ pin_page_for_write(const void __user *_addr, pte_t **ptep, spinlock_t **ptlp)
*
* Lock the page table for the destination and check
* to see that it's still huge and whether or not we will
* need to fault on write, or if we have a splitting THP.
* need to fault on write.
*/
if (unlikely(pmd_thp_or_huge(*pmd))) {
ptl = &current->mm->page_table_lock;
spin_lock(ptl);
if (unlikely(!pmd_thp_or_huge(*pmd)
|| pmd_hugewillfault(*pmd)
|| pmd_trans_splitting(*pmd))) {
|| pmd_hugewillfault(*pmd))) {
spin_unlock(ptl);
return 0;
}

15
arch/arm/mm/flush.c
View file

@ -415,18 +415,3 @@ void __flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned l
*/
__cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
pmd_t pmd = pmd_mksplitting(*pmdp);
VM_BUG_ON(address & ~PMD_MASK);
set_pmd_at(vma->vm_mm, address, pmdp, pmd);
/* dummy IPI to serialise against fast_gup */
kick_all_cpus_sync();
}
#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */