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SubjectRe: [RFC][PATCH v3 09/22] mm, s390: add gfp flags variant of pud, pte, and pte allocations
On Mon, Mar 21, 2011 at 09:34:12AM +0100, Martin Schwidefsky wrote:
> On Fri, 18 Mar 2011 19:56:44 +0000
> Prasad Joshi <prasadjoshi124@gmail.com> wrote:
>
> > - Added function __crst_table_alloc() which is similar to crst_table_alloc()
> > but accepts an extra argument gfp_t. The function uses given allocation
> > flag to allocate pages.
> >
> > - Added a function __page_table_alloc() to allocate page table entries. This
> > function is allows caller to specify the page allocation flag. The
> > allocation flag is then passed to alloc_page(). The rest of the function is
> > copy of the original page_table_alloc().
>
> The approach of this patch series seems straightforward, the only nitpick I
> have is the fact that two new functions __crst_table_alloc/__page_table_alloc
> are introduced. There aren't many call sites for the two original functions,
> namely 4 for crst_table_alloc and 3 for page_table_alloc. Why not add the
> gfp flag GFP_KERNEL to these call sites? Then the two additional functions
> would not be needed.

Thanks a lot Martin for your reply. Here is a new patch, which the changes
you suggested.

Generic changes
- Changed crst_table_alloc() to accept a new parameter gfp_t, allocate pages
using the passed allocation flag.

- crst_table_upgrade() calls crst_table_alloc() with GFP_KERNEL.

- page_table_alloc() is also changned to accept a parameter gfp_t and allocate
page using the passed allocation flag.

- vmem_pte_alloc() calls page_table_alloc() with GFP_KERNEL | __GFP_REPEAT

changes for 32 (31) bit architecture (s390)
- Added macros __pud_alloc_one, __pmd_alloc_one which are similar to
pud_alloc_one and pmd_alloc_one respectively, but has an extra argument
for gfp_t.

changes for 64 bit architecture (s390x)
- Added __pud_alloc_one() allow caller to pass the memory allocation flag.
The function passes the allocation flag to crst_table_alloc().

- The function pud_alloc_one() is modified to call __pud_alloc_one() and
pass GFP_KERNEL allocation flag.

- The similar changes are performed for pmd allocations

- pgd_populate_kernel() calls crst_table_alloc() with GFP_KERNEL

- Added marco __pte_alloc_one_kernel() to accept additional argument gfp_t.
This argument is then passed to page_table_alloc() to allocate the page
table entry.

- Modified pte_alloc_one_kernel() to call __pte_alloc_one_kernel() passing
GFP_KERNEL|__GFP_REPEAT allocation flags.

- Modified pte_alloc_one() to call page_table_alloc() with allocation flag
GFP_KERNEL | __GFP_REPEAT

- The changes for both architectures help in fixing Bug 30702

Signed-off-by: Prasad Joshi <prasadjoshi124@gmail.com>
Signed-off-by: Anand Mitra <mitra@kqinfotech.com>
---
arch/s390/include/asm/pgalloc.h | 37 ++++++++++++++++++++++++++++---------
arch/s390/mm/pgtable.c | 13 +++++++------
arch/s390/mm/vmem.c | 2 +-
3 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
index 082eb4e..8068669 100644
--- a/arch/s390/include/asm/pgalloc.h
+++ b/arch/s390/include/asm/pgalloc.h
@@ -19,11 +19,11 @@

#define check_pgt_cache() do {} while (0)

-unsigned long *crst_table_alloc(struct mm_struct *, int);
+unsigned long *crst_table_alloc(struct mm_struct *, int, gfp_t);
void crst_table_free(struct mm_struct *, unsigned long *);
void crst_table_free_rcu(struct mm_struct *, unsigned long *);

-unsigned long *page_table_alloc(struct mm_struct *);
+unsigned long *page_table_alloc(struct mm_struct *, gfp_t);
void page_table_free(struct mm_struct *, unsigned long *);
void page_table_free_rcu(struct mm_struct *, unsigned long *);
void disable_noexec(struct mm_struct *, struct task_struct *);
@@ -62,9 +62,11 @@ static inline unsigned long pgd_entry_type(struct mm_struct *mm)
return _SEGMENT_ENTRY_EMPTY;
}

+#define __pud_alloc_one(mm,address,mask) ({ BUG(); ((pud_t *)2); })
#define pud_alloc_one(mm,address) ({ BUG(); ((pud_t *)2); })
#define pud_free(mm, x) do { } while (0)

+#define __pmd_alloc_one(mm,address,mask) ({ BUG(); ((pmd_t *)2); })
#define pmd_alloc_one(mm,address) ({ BUG(); ((pmd_t *)2); })
#define pmd_free(mm, x) do { } while (0)

@@ -88,22 +90,34 @@ static inline unsigned long pgd_entry_type(struct mm_struct *mm)
int crst_table_upgrade(struct mm_struct *, unsigned long limit);
void crst_table_downgrade(struct mm_struct *, unsigned long limit);

-static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address)
+static inline pud_t *__pud_alloc_one(struct mm_struct *mm,
+ unsigned long address, gfp_t gfp_mask)
{
- unsigned long *table = crst_table_alloc(mm, mm->context.noexec);
+ unsigned long *table = crst_table_alloc(mm, mm->context.noexec, gfp_mask);
if (table)
crst_table_init(table, _REGION3_ENTRY_EMPTY);
return (pud_t *) table;
}
+
+static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address)
+{
+ return __pud_alloc_one(mm, address, GFP_KERNEL);
+}
#define pud_free(mm, pud) crst_table_free(mm, (unsigned long *) pud)

-static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
+static inline pmd_t *__pmd_alloc_one(struct mm_struct *mm,
+ unsigned long vmaddr, gfp_t gfp_mask)
{
- unsigned long *table = crst_table_alloc(mm, mm->context.noexec);
+ unsigned long *table = crst_table_alloc(mm, mm->context.noexec, gfp_mask);
if (table)
crst_table_init(table, _SEGMENT_ENTRY_EMPTY);
return (pmd_t *) table;
}
+
+static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long vmaddr)
+{
+ return __pmd_alloc_one(mm, vmaddr, GFP_KERNEL);
+}
#define pmd_free(mm, pmd) crst_table_free(mm, (unsigned long *) pmd)

static inline void pgd_populate_kernel(struct mm_struct *mm,
@@ -146,7 +160,7 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
INIT_LIST_HEAD(&mm->context.crst_list);
INIT_LIST_HEAD(&mm->context.pgtable_list);
return (pgd_t *)
- crst_table_alloc(mm, user_mode == SECONDARY_SPACE_MODE);
+ crst_table_alloc(mm, user_mode == SECONDARY_SPACE_MODE, GFP_KERNEL);
}
#define pgd_free(mm, pgd) crst_table_free(mm, (unsigned long *) pgd)

@@ -172,8 +186,13 @@ static inline void pmd_populate(struct mm_struct *mm,
/*
* page table entry allocation/free routines.
*/
-#define pte_alloc_one_kernel(mm, vmaddr) ((pte_t *) page_table_alloc(mm))
-#define pte_alloc_one(mm, vmaddr) ((pte_t *) page_table_alloc(mm))
+#define __pte_alloc_one_kernel(mm, vmaddr, mask) \
+ ((pte_t *) page_table_alloc((mm), (mask)))
+#define pte_alloc_one_kernel(mm, vmaddr) \
+ ((pte_t *) __pte_alloc_one_kernel((mm), (vmaddr), GFP_KERNEL|__GFP_REPEAT)
+
+#define pte_alloc_one(mm, vmaddr) \
+ ((pte_t *) page_table_alloc((mm), GFP_KERNEL | __GFP_REPEAT))

#define pte_free_kernel(mm, pte) page_table_free(mm, (unsigned long *) pte)
#define pte_free(mm, pte) page_table_free(mm, (unsigned long *) pte)
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index e1850c2..9bf1632 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -125,15 +125,16 @@ static int __init parse_vmalloc(char *arg)
}
early_param("vmalloc", parse_vmalloc);

-unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec)
+unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec,
+ gfp_t gfp_mask)
{
- struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
+ struct page *page = alloc_pages(gfp_mask, ALLOC_ORDER);

if (!page)
return NULL;
page->index = 0;
if (noexec) {
- struct page *shadow = alloc_pages(GFP_KERNEL, ALLOC_ORDER);
+ struct page *shadow = alloc_pages(gfp_mask, ALLOC_ORDER);
if (!shadow) {
__free_pages(page, ALLOC_ORDER);
return NULL;
@@ -197,7 +198,7 @@ int crst_table_upgrade(struct mm_struct *mm, unsigned long limit)

BUG_ON(limit > (1UL << 53));
repeat:
- table = crst_table_alloc(mm, mm->context.noexec);
+ table = crst_table_alloc(mm, mm->context.noexec, GFP_KERNEL);
if (!table)
return -ENOMEM;
spin_lock_bh(&mm->page_table_lock);
@@ -267,7 +268,7 @@ void crst_table_downgrade(struct mm_struct *mm, unsigned long limit)
/*
* page table entry allocation/free routines.
*/
-unsigned long *page_table_alloc(struct mm_struct *mm)
+unsigned long *page_table_alloc(struct mm_struct *mm, gfp_t gfp_mask)
{
struct page *page;
unsigned long *table;
@@ -284,7 +285,7 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
}
if (!page) {
spin_unlock_bh(&mm->context.list_lock);
- page = alloc_page(GFP_KERNEL|__GFP_REPEAT);
+ page = alloc_page(gfp_mask);
if (!page)
return NULL;
pgtable_page_ctor(page);
diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index 34c43f2..f7e8716 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -66,7 +66,7 @@ static pte_t __ref *vmem_pte_alloc(void)
pte_t *pte;

if (slab_is_available())
- pte = (pte_t *) page_table_alloc(&init_mm);
+ pte = (pte_t *) page_table_alloc(&init_mm, GFP_KERNEL | __GFP_REPEAT);
else
pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t));
if (!pte)
--
1.7.0.4

>
> --
> blue skies,
> Martin.
>
> "Reality continues to ruin my life." - Calvin.
>


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