From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-mm@kvack.org
Cc: Andi Kleen <ak@linux.intel.com>,
"H. Peter Anvin" <hpa@linux.intel.com>,
linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill@shutemov.name>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCH, RFC 3/9] thp: copy_huge_pmd(): copy huge zero page
Date: Thu, 9 Aug 2012 12:08:14 +0300 [thread overview]
Message-ID: <1344503300-9507-4-git-send-email-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <1344503300-9507-1-git-send-email-kirill.shutemov@linux.intel.com>
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
It's easy to copy huge zero page. Just set destination pmd to huge zero
page.
It's safe to copy huge zero page since we have none yet :-p
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
mm/huge_memory.c | 17 +++++++++++++++++
1 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 9dcb9e6..a534f84 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -725,6 +725,18 @@ static inline struct page *alloc_hugepage(int defrag)
}
#endif
+static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
+ struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd)
+{
+ pmd_t entry;
+ entry = pfn_pmd(huge_zero_pfn, vma->vm_page_prot);
+ entry = pmd_wrprotect(entry);
+ entry = pmd_mkhuge(entry);
+ set_pmd_at(mm, haddr, pmd, entry);
+ prepare_pmd_huge_pte(pgtable, mm);
+ mm->nr_ptes++;
+}
+
int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd,
unsigned int flags)
@@ -802,6 +814,11 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pte_free(dst_mm, pgtable);
goto out_unlock;
}
+ if (is_huge_zero_pmd(pmd)) {
+ set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd);
+ ret = 0;
+ goto out_unlock;
+ }
if (unlikely(pmd_trans_splitting(pmd))) {
/* split huge page running from under us */
spin_unlock(&src_mm->page_table_lock);
--
1.7.7.6
next prev parent reply other threads:[~2012-08-09 9:08 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-09 9:08 [PATCH, RFC 0/9] Introduce huge zero page Kirill A. Shutemov
2012-08-09 9:08 ` [PATCH, RFC 1/9] thp: huge zero page: basic preparation Kirill A. Shutemov
2012-08-09 9:08 ` [PATCH, RFC 2/9] thp: zap_huge_pmd(): zap huge zero pmd Kirill A. Shutemov
2012-08-09 9:08 ` Kirill A. Shutemov [this message]
2012-08-09 9:08 ` [PATCH, RFC 4/9] thp: do_huge_pmd_wp_page(): handle huge zero page Kirill A. Shutemov
2012-08-09 9:08 ` [PATCH, RFC 5/9] thp: change_huge_pmd(): keep huge zero page write-protected Kirill A. Shutemov
2012-08-09 9:08 ` [PATCH, RFC 6/9] thp: add address parameter to split_huge_page_pmd() Kirill A. Shutemov
2012-08-16 19:42 ` Andrea Arcangeli
2012-08-17 7:49 ` Kirill A. Shutemov
2012-08-09 9:08 ` [PATCH, RFC 7/9] thp: implement splitting pmd for huge zero page Kirill A. Shutemov
2012-08-16 19:27 ` Andrea Arcangeli
2012-08-17 8:12 ` Kirill A. Shutemov
2012-08-17 16:33 ` Andrea Arcangeli
2012-08-31 14:06 ` Kirill A. Shutemov
2012-08-09 9:08 ` [PATCH, RFC 8/9] thp: setup huge zero page on non-write page fault Kirill A. Shutemov
2012-08-09 9:08 ` [PATCH, RFC 9/9] thp: lazy huge zero page allocation Kirill A. Shutemov
[not found] ` <20120810034912.GA31071@hacker.(null)>
2012-08-10 10:33 ` [PATCH, RFC 0/9] Introduce huge zero page Kirill A. Shutemov
2012-08-16 19:20 ` Andrew Morton
2012-08-16 19:40 ` Andrea Arcangeli
2012-08-16 23:08 ` H. Peter Anvin
2012-08-16 23:12 ` Andi Kleen
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