From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964840Ab2HWRTL (ORCPT ); Thu, 23 Aug 2012 13:19:11 -0400 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:59472 "EHLO e06smtp17.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758767Ab2HWRTC (ORCPT ); Thu, 23 Aug 2012 13:19:02 -0400 Message-Id: <20120823171854.792085547@de.ibm.com> User-Agent: quilt/0.47-1 Date: Thu, 23 Aug 2012 19:17:38 +0200 From: Gerald Schaefer To: akpm@linux-foundation.org, aarcange@redhat.com, linux-mm@kvack.org, ak@linux.intel.com, hughd@google.com Cc: linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, gerald.schaefer@de.ibm.com Subject: [RFC patch 5/7] thp, s390: thp pagetable pre-allocation for System z References: <20120823171733.595087166@de.ibm.com> Content-Disposition: inline; filename=linux-3.5-thp-s390-pgtable.patch x-cbid: 12082317-0542-0000-0000-000002CF19D7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch is part of the architecture backend for thp on System z. It provides the pagetable pre-allocation functions pgtable_deposit() and pgtable_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: Gerald Schaefer --- arch/s390/include/asm/pgtable.h | 6 ++++++ arch/s390/mm/pgtable.c | 38 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -1166,6 +1166,12 @@ static inline pmd_t *pmd_offset(pud_t *p #define pte_unmap(pte) do { } while (0) #ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define __HAVE_ARCH_PGTABLE_DEPOSIT +extern void pgtable_deposit(struct mm_struct *mm, pgtable_t pgtable); + +#define __HAVE_ARCH_PGTABLE_WITHDRAW +extern pgtable_t pgtable_withdraw(struct mm_struct *mm); + static inline int pmd_trans_splitting(pmd_t pmd) { return pmd_val(pmd) & _SEGMENT_ENTRY_SPLIT; --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -883,4 +883,42 @@ void pmdp_splitting_flush(struct vm_area smp_call_function(pmdp_splitting_flush_sync, NULL, 1); } } + +void pgtable_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_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 */