[patch 09/10] Hugetlb common code update for System z.

Martin Schwidefsky
2008-03-12T17:34:45Z

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From: Gerald Schaefer <geraldsc@de.ibm.com>

Huge ptes have a special type on s390 and cannot be handled with the
standard pte functions in certain cases. This patch adds some new
architecture-specific definitions and functions to hugetlb common code,
as a prerequisite for the System z large page support. They won't
affect other architectures.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

include/linux/hugetlb.h | 18 ++++++++++++++++++
mm/hugetlb.c | 36 +++++++++++++++++++++---------------
2 files changed, 39 insertions(+), 15 deletions(-)

Index: quilt-2.6/include/linux/hugetlb.h
===================================================================
--- quilt-2.6.orig/include/linux/hugetlb.h
+++ quilt-2.6/include/linux/hugetlb.h
@@ -80,6 +80,24 @@ static inline int prepare_hugepage_range
int prepare_hugepage_range(unsigned long addr, unsigned long len);
#endif

+#ifndef ARCH_HAS_HUGE_PTE_TYPE
+#define huge_pte_none(pte) pte_none(pte)
+#define huge_pte_wrprotect(pte) pte_wrprotect(pte)
+#define huge_ptep_set_wrprotect(mm, addr, ptep) \
+ ptep_set_wrprotect(mm, addr, ptep)
+#define huge_ptep_set_access_flags(vma, addr, ptep, pte, dirty) \
+ ptep_set_access_flags(vma, addr, ptep, pte, dirty)
+#define huge_ptep_get(ptep) (*ptep)
+#endif
+
+#ifndef ARCH_HAS_PREPARE_HUGEPAGE
+#define arch_prepare_hugepage(page) 0
+#define arch_release_hugepage(page) do { } while (0)
+#else
+int arch_prepare_hugepage(struct page *page);
+void arch_release_hugepage(struct page *page);
+#endif
+
#ifndef ARCH_HAS_HUGEPAGE_CLEAR_FLUSH
#define huge_ptep_clear_flush(vma, addr, ptep) do { } while (0)
#endif
Index: quilt-2.6/mm/hugetlb.c
===================================================================
--- quilt-2.6.orig/mm/hugetlb.c
+++ quilt-2.6/mm/hugetlb.c
@@ -129,6 +129,7 @@ static void update_and_free_page(struct
}
set_compound_page_dtor(page, NULL);
set_page_refcounted(page);
+ arch_release_hugepage(page);
__free_pages(page, HUGETLB_PAGE_ORDER);
}

@@ -198,6 +199,10 @@ static struct page *alloc_fresh_huge_pag
htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN,
HUGETLB_PAGE_ORDER);
if (page) {
+ if (arch_prepare_hugepage(page)) {
+ __free_pages(page, HUGETLB_PAGE_ORDER);
+ return 0;
+ }
set_compound_page_dtor(page, free_huge_page);
spin_lock(&hugetlb_lock);
nr_huge_pages++;
@@ -707,7 +712,7 @@ static pte_t make_huge_pte(struct vm_are
entry =
pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
} else {
- entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
+ entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
}
entry = pte_mkyoung(entry);
entry = pte_mkhuge(entry);
@@ -720,8 +725,8 @@ static void set_huge_ptep_writable(struc
{
pte_t entry;

- entry = pte_mkwrite(pte_mkdirty(*ptep));
- if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
+ entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
+ if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
update_mmu_cache(vma, address, entry);
}
}
@@ -751,10 +756,10 @@ int copy_hugetlb_page_range(struct mm_st

spin_lock(&dst->page_table_lock);
spin_lock(&src->page_table_lock);
- if (!pte_none(*src_pte)) {
+ if (!huge_pte_none(huge_ptep_get(src_pte))) {
if (cow)
- ptep_set_wrprotect(src, addr, src_pte);
- entry = *src_pte;
+ huge_ptep_set_wrprotect(src, addr, src_pte);
+ entry = huge_ptep_get(src_pte);
ptepage = pte_page(entry);
get_page(ptepage);
set_huge_pte_at(dst, addr, dst_pte, entry);
@@ -798,7 +803,7 @@ void __unmap_hugepage_range(struct vm_ar
continue;

pte = huge_ptep_get_and_clear(mm, address, ptep);
- if (pte_none(pte))
+ if (huge_pte_none(pte))
continue;

page = pte_page(pte);
@@ -862,7 +867,7 @@ static int hugetlb_cow(struct mm_struct
spin_lock(&mm->page_table_lock);

ptep = huge_pte_offset(mm, address & HPAGE_MASK);
- if (likely(pte_same(*ptep, pte))) {
+ if (likely(pte_same(huge_ptep_get(ptep), pte))) {
/* Break COW */
huge_ptep_clear_flush(vma, address, ptep);
set_huge_pte_at(mm, address, ptep,
@@ -932,7 +937,7 @@ retry:
goto backout;

ret = 0;
- if (!pte_none(*ptep))
+ if (!huge_pte_none(huge_ptep_get(ptep)))
goto backout;

new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
@@ -974,8 +979,8 @@ int hugetlb_fault(struct mm_struct *mm,
* the same page in the page cache.
*/
mutex_lock(&hugetlb_instantiation_mutex);
- entry = *ptep;
- if (pte_none(entry)) {
+ entry = huge_ptep_get(ptep);
+ if (huge_pte_none(entry)) {
ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
mutex_unlock(&hugetlb_instantiation_mutex);
return ret;
@@ -985,7 +990,7 @@ int hugetlb_fault(struct mm_struct *mm,

spin_lock(&mm->page_table_lock);
/* Check for a racing update before calling hugetlb_cow */
- if (likely(pte_same(entry, *ptep)))
+ if (likely(pte_same(entry, huge_ptep_get(ptep))))
if (write_access && !pte_write(entry))
ret = hugetlb_cow(mm, vma, address, ptep, entry);
spin_unlock(&mm->page_table_lock);
@@ -1015,7 +1020,8 @@ int follow_hugetlb_page(struct mm_struct
*/
pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);

- if (!pte || pte_none(*pte) || (write && !pte_write(*pte))) {
+ if (!pte || huge_pte_none(huge_ptep_get(pte)) ||
+ (write && !pte_write(huge_ptep_get(pte)))) {
int ret;

spin_unlock(&mm->page_table_lock);
@@ -1031,7 +1037,7 @@ int follow_hugetlb_page(struct mm_struct
}

pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT;
- page = pte_page(*pte);
+ page = pte_page(huge_ptep_get(pte));
same_page:
if (pages) {
get_page(page);
@@ -1080,7 +1086,7 @@ void hugetlb_change_protection(struct vm
continue;
if (huge_pmd_unshare(mm, &address, ptep))
continue;
- if (!pte_none(*ptep)) {
+ if (!huge_pte_none(huge_ptep_get(ptep))) {
pte = huge_ptep_get_and_clear(mm, address, ptep);
pte = pte_mkhuge(pte_modify(pte, newprot));
set_huge_pte_at(mm, address, ptep, pte);

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.