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Commit 9501d09f authored by Gerald Schaefer's avatar Gerald Schaefer Committed by Linus Torvalds
Browse files

thp, s390: thp pagetable pre-allocation for s390 



This patch is part of the architecture backend for thp on s390.  It
provides the pagetable pre-allocation functions
pgtable_trans_huge_deposit() and pgtable_trans_huge_withdraw().  Unlike
other archs, s390 has no struct page * as pgtable_t, but rather a pointer
to the page table.  So instead of saving the pagetable pre- allocation
list info inside the struct page, it is being saved within the pagetable
itself.

Signed-off-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 75077afb

arch/s390/include/asm/pgtable.h

+6 −0
Original line number Diff line number Diff line
@@ -1166,6 +1166,12 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) 
#define pte_unmap(pte) do { } while (0)



#ifdef CONFIG_TRANSPARENT_HUGEPAGE

#define __HAVE_ARCH_PGTABLE_DEPOSIT

extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable);



#define __HAVE_ARCH_PGTABLE_WITHDRAW

extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm);



static inline int pmd_trans_splitting(pmd_t pmd)

{

	return pmd_val(pmd) & _SEGMENT_ENTRY_SPLIT;

arch/s390/mm/pgtable.c

+38 −0
Original line number Diff line number Diff line
@@ -883,4 +883,42 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address, 
		smp_call_function(pmdp_splitting_flush_sync, NULL, 1);

	}

}



void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)

{

	struct list_head *lh = (struct list_head *) pgtable;



	assert_spin_locked(&mm->page_table_lock);



	/* FIFO */

	if (!mm->pmd_huge_pte)

		INIT_LIST_HEAD(lh);

	else

		list_add(lh, (struct list_head *) mm->pmd_huge_pte);

	mm->pmd_huge_pte = pgtable;

}



pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)

{

	struct list_head *lh;

	pgtable_t pgtable;

	pte_t *ptep;



	assert_spin_locked(&mm->page_table_lock);



	/* FIFO */

	pgtable = mm->pmd_huge_pte;

	lh = (struct list_head *) pgtable;

	if (list_empty(lh))

		mm->pmd_huge_pte = NULL;

	else {

		mm->pmd_huge_pte = (pgtable_t) lh->next;

		list_del(lh);

	}

	ptep = (pte_t *) pgtable;

	pte_val(*ptep) = _PAGE_TYPE_EMPTY;

	ptep++;

	pte_val(*ptep) = _PAGE_TYPE_EMPTY;

	return pgtable;

}

#endif /* CONFIG_TRANSPARENT_HUGEPAGE */