[RFC][PATCH 2/2]: MM: Make Page Tables Relocatable

From: Ross Biro
Date: Wed Jan 23 2008 - 11:15:56 EST


---
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/i386/mm/hugetlbpage.c 2.6.23a/arch/i386/mm/hugetlbpage.c
--- 2.6.23/arch/i386/mm/hugetlbpage.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/i386/mm/hugetlbpage.c 2007-10-29 09:48:48.000000000 -0700
@@ -87,6 +87,7 @@ static void huge_pmd_share(struct mm_str
goto out;

spin_lock(&mm->page_table_lock);
+ delimbo_pud(&pud, mm, addr);
if (pud_none(*pud))
pud_populate(mm, pud, (unsigned long) spte & PAGE_MASK);
else
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/powerpc/mm/fault.c 2.6.23a/arch/powerpc/mm/fault.c
--- 2.6.23/arch/powerpc/mm/fault.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/powerpc/mm/fault.c 2007-10-29 09:38:09.000000000 -0700
@@ -301,6 +301,8 @@ good_area:
if (get_pteptr(mm, address, &ptep, &pmdp)) {
spinlock_t *ptl = pte_lockptr(mm, pmdp);
spin_lock(ptl);
+ delimbo_pte(&ptep, &ptl, &pmdp, mm, address);
+
if (pte_present(*ptep)) {
struct page *page = pte_page(*ptep);

diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/powerpc/mm/hugetlbpage.c 2.6.23a/arch/powerpc/mm/hugetlbpage.c
--- 2.6.23/arch/powerpc/mm/hugetlbpage.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/powerpc/mm/hugetlbpage.c 2007-10-29 09:53:36.000000000 -0700
@@ -77,6 +77,7 @@ static int __hugepte_alloc(struct mm_str
return -ENOMEM;

spin_lock(&mm->page_table_lock);
+ delimbo_hpd(&hpdp, mm, address);
if (!hugepd_none(*hpdp))
kmem_cache_free(huge_pgtable_cache, new);
else
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/ppc/mm/fault.c 2.6.23a/arch/ppc/mm/fault.c
--- 2.6.23/arch/ppc/mm/fault.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/ppc/mm/fault.c 2007-10-29 09:38:19.000000000 -0700
@@ -219,6 +219,7 @@ good_area:
if (get_pteptr(mm, address, &ptep, &pmdp)) {
spinlock_t *ptl = pte_lockptr(mm, pmdp);
spin_lock(ptl);
+ delimbo_pte(&ptep, &ptl, &pmdp, mm, address);
if (pte_present(*ptep)) {
struct page *page = pte_page(*ptep);

diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/arch/x86_64/kernel/smp.c 2.6.23a/arch/x86_64/kernel/smp.c
--- 2.6.23/arch/x86_64/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/x86_64/kernel/smp.c 2008-01-14 10:46:49.000000000 -0800
@@ -56,6 +56,7 @@ union smp_flush_state {
struct mm_struct *flush_mm;
unsigned long flush_va;
#define FLUSH_ALL -1ULL
+#define RELOAD_ALL -2ULL
spinlock_t tlbstate_lock;
};
char pad[SMP_CACHE_BYTES];
@@ -155,6 +156,8 @@ asmlinkage void smp_invalidate_interrupt
if (read_pda(mmu_state) == TLBSTATE_OK) {
if (f->flush_va == FLUSH_ALL)
local_flush_tlb();
+ else if (f->flush_va == RELOAD_ALL)
+ local_reload_tlb_mm(f->flush_mm);
else
__flush_tlb_one(f->flush_va);
} else
@@ -225,10 +228,36 @@ void flush_tlb_current_task(void)
}
EXPORT_SYMBOL(flush_tlb_current_task);

+void reload_tlb_mm(struct mm_struct *mm)
+{
+ cpumask_t cpu_mask;
+
+ clear_bit(MMF_NEED_RELOAD, &mm->flags);
+ clear_bit(MMF_NEED_FLUSH, &mm->flags);
+
+ preempt_disable();
+ cpu_mask = mm->cpu_vm_mask;
+ cpu_clear(smp_processor_id(), cpu_mask);
+
+ if (current->active_mm == mm) {
+ if (current->mm)
+ local_reload_tlb_mm(mm);
+ else
+ leave_mm(smp_processor_id());
+ }
+ if (!cpus_empty(cpu_mask))
+ flush_tlb_others(cpu_mask, mm, RELOAD_ALL);
+
+ preempt_enable();
+
+}
+
void flush_tlb_mm (struct mm_struct * mm)
{
cpumask_t cpu_mask;

+ clear_bit(MMF_NEED_FLUSH, &mm->flags);
+
preempt_disable();
cpu_mask = mm->cpu_vm_mask;
cpu_clear(smp_processor_id(), cpu_mask);
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/include/asm-generic/pgtable.h 2.6.23a/include/asm-generic/pgtable.h
--- 2.6.23/include/asm-generic/pgtable.h 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/include/asm-generic/pgtable.h 2008-01-08 08:00:34.000000000 -0800
@@ -4,6 +4,8 @@
#ifndef __ASSEMBLY__
#ifdef CONFIG_MMU

+#include <linux/sched.h>
+
#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
/*
* Largely same as above, but only sets the access flags (dirty,
@@ -199,6 +201,49 @@ static inline int pmd_none_or_clear_bad(
}
return 0;
}
+
+
+/* Used to rewalk the page tables if after we grab the appropriate lock,
+ we end up with a page that's just waiting to go away. */
+static inline pgd_t *walk_page_table_pgd(struct mm_struct *mm,
+ unsigned long addr)
+{
+ return pgd_offset(mm, addr);
+}
+
+static inline pud_t *walk_page_table_pud(struct mm_struct *mm,
+ unsigned long addr) {
+ pgd_t *pgd;
+ pgd = walk_page_table_pgd(mm, addr);
+ BUG_ON(!pgd);
+ return pud_offset(pgd, addr);
+}
+
+static inline pmd_t *walk_page_table_pmd(struct mm_struct *mm,
+ unsigned long addr)
+{
+ pud_t *pud;
+ pud = walk_page_table_pud(mm, addr);
+ BUG_ON(!pud);
+ return pmd_offset(pud, addr);
+}
+
+static inline pte_t *walk_page_table_pte(struct mm_struct *mm,
+ unsigned long addr)
+{
+ pmd_t *pmd;
+ pmd = walk_page_table_pmd(mm, addr);
+ BUG_ON(!pmd);
+ return pte_offset_map(pmd, addr);
+}
+
+static inline pte_t *walk_page_table_huge_pte(struct mm_struct *mm,
+ unsigned long addr)
+{
+ return (pte_t *)walk_page_table_pmd(mm, addr);
+}
+
+
#endif /* CONFIG_MMU */

/*
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/include/asm-x86_64/tlbflush.h 2.6.23a/include/asm-x86_64/tlbflush.h
--- 2.6.23/include/asm-x86_64/tlbflush.h 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/include/asm-x86_64/tlbflush.h 2008-01-11 08:31:06.000000000 -0800
@@ -6,6 +6,13 @@
#include <asm/processor.h>
#include <asm/system.h>

+#define ARCH_HAS_RELOAD_TLB
+static inline void load_cr3(pgd_t *pgd);
+static inline void __reload_tlb_mm(struct mm_struct *mm)
+{
+ load_cr3(mm->pgd);
+}
+
static inline void __flush_tlb(void)
{
write_cr3(read_cr3());
@@ -44,6 +50,12 @@ static inline void __flush_tlb_all(void)
#define flush_tlb_all() __flush_tlb_all()
#define local_flush_tlb() __flush_tlb()

+static inline void reload_tlb_mm(struct mm_struct *mm)
+{
+ if (mm == current->active_mm)
+ __reload_tlb_mm(mm);
+}
+
static inline void flush_tlb_mm(struct mm_struct *mm)
{
if (mm == current->active_mm)
@@ -71,6 +83,10 @@ static inline void flush_tlb_range(struc
#define local_flush_tlb() \
__flush_tlb()

+#define local_reload_tlb_mm(mm) \
+ __reload_tlb_mm(mm)
+
+extern void reload_tlb_mm(struct mm_struct *mm);
extern void flush_tlb_all(void);
extern void flush_tlb_current_task(void);
extern void flush_tlb_mm(struct mm_struct *);
@@ -106,4 +122,6 @@ static inline void flush_tlb_pgtables(st
by the normal TLB flushing algorithms. */
}

+#include <asm-generic/tlbflush.h>
+
#endif /* _X8664_TLBFLUSH_H */
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/include/linux/mm.h 2.6.23a/include/linux/mm.h
--- 2.6.23/include/linux/mm.h 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/include/linux/mm.h 2008-01-02 08:07:47.000000000 -0800
@@ -14,6 +14,7 @@
#include <linux/debug_locks.h>
#include <linux/backing-dev.h>
#include <linux/mm_types.h>
+#include <asm/pgtable.h>

struct mempolicy;
struct anon_vma;
@@ -935,6 +936,7 @@ static inline pmd_t *pmd_alloc(struct mm
pte_t *__pte = pte_offset_map(pmd, address); \
*(ptlp) = __ptl; \
spin_lock(__ptl); \
+ delimbo_pte(&__pte, ptlp, &pmd, mm, address); \
__pte; \
})

@@ -959,6 +962,62 @@ extern void free_area_init(unsigned long
extern void free_area_init_node(int nid, pg_data_t *pgdat,
unsigned long * zones_size, unsigned long zone_start_pfn,
unsigned long *zholes_size);
+
+
+
+static inline void delimbo_pte(pte_t **pte, spinlock_t **ptl, pmd_t **pmd,
+ struct mm_struct *mm,
+ unsigned long addr)
+{
+#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
+ spin_unlock(*ptl);
+#endif
+ pte_unmap(*pte);
+ *pmd = walk_page_table_pmd(mm, addr);
+ *pte = pte_offset_map(*pmd, addr);
+ *ptl = pte_lockptr(mm, *pmd);
+#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
+ spin_lock(*ptl);
+#endif
+}
+
+static inline void delimbo_pte_nested(pte_t **pte, spinlock_t **ptl,
+ pmd_t **pmd,
+ struct mm_struct *mm,
+ unsigned long addr, int subclass)
+{
+#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
+ spin_unlock(*ptl);
+#endif
+ *pmd = walk_page_table_pmd(mm, addr);
+ *pte = pte_offset_map(*pmd, addr);
+ *ptl = pte_lockptr(mm, *pmd);
+
+#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
+ spin_lock_nested(*ptl, subclass);
+#endif
+}
+
+static inline void delimbo_pud(pud_t **pud, struct mm_struct *mm,
+ unsigned long addr) {
+ *pud = walk_page_table_pud(mm, addr);
+}
+
+static inline void delimbo_pmd(pmd_t **pmd, struct mm_struct *mm,
+ unsigned long addr) {
+ *pmd = walk_page_table_pmd(mm, addr);
+}
+
+static inline void delimbo_pgd(pgd_t **pgd, struct mm_struct *mm,
+ unsigned long addr) {
+ *pgd = walk_page_table_pgd(mm, addr);
+}
+
+static inline void delimbo_huge_pte(pte_t **pte, struct mm_struct *mm,
+ unsigned long addr) {
+ *pte = walk_page_table_huge_pte(mm, addr);
+}
+
#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
/*
* With CONFIG_ARCH_POPULATES_NODE_MAP set, an architecture may initialise its
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/include/linux/mm_types.h 2.6.23a/include/linux/mm_types.h
--- 2.6.23/include/linux/mm_types.h 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/include/linux/mm_types.h 2008-01-02 08:06:09.000000000 -0800
@@ -5,6 +5,7 @@
#include <linux/threads.h>
#include <linux/list.h>
#include <linux/spinlock.h>
+#include <linux/rcupdate.h>

struct address_space;

@@ -61,9 +62,18 @@ struct page {
pgoff_t index; /* Our offset within mapping. */
void *freelist; /* SLUB: freelist req. slab lock */
};
+
+ union {
struct list_head lru; /* Pageout list, eg. active_list
* protected by zone->lru_lock !
*/
+ struct rcu_head rcu; /* Used by page table relocation code
+ * to remember page for later freeing,
+ * after we are sure anyone
+ * poking at the page tables is no
+ * longer looking at this page.
+ */
+ };
/*
* On machines where all RAM is mapped into kernel address space,
* we can simply calculate the virtual address. On machines with
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/mm/hugetlb.c 2.6.23a/mm/hugetlb.c
--- 2.6.23/mm/hugetlb.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/mm/hugetlb.c 2007-10-30 07:32:50.000000000 -0700
@@ -379,6 +379,8 @@ int copy_hugetlb_page_range(struct mm_st
goto nomem;
spin_lock(&dst->page_table_lock);
spin_lock(&src->page_table_lock);
+ delimbo_huge_pte(&src_pte, src, addr);
+ delimbo_huge_pte(&dst_pte, dst, addr);
if (!pte_none(*src_pte)) {
if (cow)
ptep_set_wrprotect(src, addr, src_pte);
@@ -551,6 +553,7 @@ retry:
}

spin_lock(&mm->page_table_lock);
+ delimbo_huge_pte(&ptep, mm, address);
size = i_size_read(mapping->host) >> HPAGE_SHIFT;
if (idx >= size)
goto backout;
@@ -609,6 +612,7 @@ int hugetlb_fault(struct mm_struct *mm,
ret = 0;

spin_lock(&mm->page_table_lock);
+ delimbo_huge_pte(&ptep, mm, address);
/* Check for a racing update before calling hugetlb_cow */
if (likely(pte_same(entry, *ptep)))
if (write_access && !pte_write(entry))
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/mm/memory.c 2.6.23a/mm/memory.c
--- 2.6.23/mm/memory.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/mm/memory.c 2008-01-11 10:50:42.000000000 -0800
@@ -306,6 +306,7 @@ int __pte_alloc(struct mm_struct *mm, pm

pte_lock_init(new);
spin_lock(&mm->page_table_lock);
+ delimbo_pmd(&pmd, mm, address);
if (pmd_present(*pmd)) { /* Another has populated it */
pte_lock_deinit(new);
pte_free(new);
@@ -325,6 +326,7 @@ int __pte_alloc_kernel(pmd_t *pmd, unsig
return -ENOMEM;

spin_lock(&init_mm.page_table_lock);
+ delimbo_pmd(&pmd, &init_mm, address);
if (pmd_present(*pmd)) /* Another has populated it */
pte_free_kernel(new);
else
@@ -504,6 +506,8 @@ again:
src_pte = pte_offset_map_nested(src_pmd, addr);
src_ptl = pte_lockptr(src_mm, src_pmd);
spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
+
+ delimbo_pte(&src_pte, &src_ptl, &src_pmd, src_mm, addr);
arch_enter_lazy_mmu_mode();

do {
@@ -1558,13 +1562,15 @@ EXPORT_SYMBOL_GPL(apply_to_page_range);
* and do_anonymous_page and do_no_page can safely check later on).
*/
static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
- pte_t *page_table, pte_t orig_pte)
+ pte_t *page_table, pte_t orig_pte,
+ unsigned long address)
{
int same = 1;
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
if (sizeof(pte_t) > sizeof(unsigned long)) {
spinlock_t *ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
+ delimbo_pte(&page_table, &ptl, &pmd, mm, address);
same = pte_same(*page_table, orig_pte);
spin_unlock(ptl);
}
@@ -2153,7 +2159,7 @@ static int do_swap_page(struct mm_struct
pte_t pte;
int ret = 0;

- if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+ if (!pte_unmap_same(mm, pmd, page_table, orig_pte, address))
goto out;

entry = pte_to_swp_entry(orig_pte);
@@ -2227,6 +2233,10 @@ static int do_swap_page(struct mm_struct
}

/* No need to invalidate - it was non-present before */
+ /* Unless of course the cpu might be looking at an old
+ copy of the pte. */
+ maybe_reload_tlb_mm(mm);
+
update_mmu_cache(vma, address, pte);
unlock:
pte_unmap_unlock(page_table, ptl);
@@ -2279,6 +2289,7 @@ static int do_anonymous_page(struct mm_s

ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
+ delimbo_pte(&page_table, &ptl, &pmd, mm, address);
if (!pte_none(*page_table))
goto release;
inc_mm_counter(mm, file_rss);
@@ -2288,6 +2299,10 @@ static int do_anonymous_page(struct mm_s
set_pte_at(mm, address, page_table, entry);

/* No need to invalidate - it was non-present before */
+ /* Unless of course the cpu might be looking at an old
+ copy of the pte. */
+ maybe_reload_tlb_mm(mm);
+
update_mmu_cache(vma, address, entry);
lazy_mmu_prot_update(entry);
unlock:
@@ -2441,6 +2456,10 @@ static int __do_fault(struct mm_struct *
}

/* no need to invalidate: a not-present page won't be cached */
+ /* Unless of course the cpu could be looking at an old page
+ table entry. */
+ maybe_reload_tlb_mm(mm);
+
update_mmu_cache(vma, address, entry);
lazy_mmu_prot_update(entry);
} else {
@@ -2544,7 +2563,7 @@ static int do_nonlinear_fault(struct mm_
(write_access ? FAULT_FLAG_WRITE : 0);
pgoff_t pgoff;

- if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
+ if (!pte_unmap_same(mm, pmd, page_table, orig_pte, address))
return 0;

if (unlikely(!(vma->vm_flags & VM_NONLINEAR) ||
@@ -2603,6 +2622,7 @@ static inline int handle_pte_fault(struc

ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
+ delimbo_pte(&pte, &ptl, &pmd, mm, address);
if (unlikely(!pte_same(*pte, entry)))
goto unlock;
if (write_access) {
@@ -2625,6 +2645,12 @@ static inline int handle_pte_fault(struc
if (write_access)
flush_tlb_page(vma, address);
}
+
+ /* if the cpu could be looking at an old page table, we need to
+ flush out everything. */
+ maybe_reload_tlb_mm(mm);
+
+
unlock:
pte_unmap_unlock(pte, ptl);
return 0;
@@ -2674,6 +2700,7 @@ int __pud_alloc(struct mm_struct *mm, pg
return -ENOMEM;

spin_lock(&mm->page_table_lock);
+ delimbo_pgd(&pgd, mm, address);
if (pgd_present(*pgd)) /* Another has populated it */
pud_free(new);
else
@@ -2695,6 +2722,7 @@ int __pmd_alloc(struct mm_struct *mm, pu
return -ENOMEM;

spin_lock(&mm->page_table_lock);
+ delimbo_pud(&pud, mm, address);
#ifndef __ARCH_HAS_4LEVEL_HACK
if (pud_present(*pud)) /* Another has populated it */
pmd_free(new);
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/mm/mempolicy.c 2.6.23a/mm/mempolicy.c
--- 2.6.23/mm/mempolicy.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/mm/mempolicy.c 2008-01-11 10:04:11.000000000 -0800
@@ -101,6 +101,11 @@
static struct kmem_cache *policy_cache;
static struct kmem_cache *sn_cache;

+
+int migrate_page_tables_mm(struct mm_struct *mm, int source,
+ new_page_t get_new_page, unsigned long private);
+
+
/* Highest zone. An specific allocation for a zone below that is not
policied. */
enum zone_type policy_zone = 0;
@@ -597,6 +602,11 @@ static struct page *new_node_page(struct
return alloc_pages_node(node, GFP_HIGHUSER_MOVABLE, 0);
}

+static struct page *new_node_page_page_tables(struct page *page,
+ unsigned long node, int **x) {
+ return alloc_pages_node(node, GFP_KERNEL, 0);
+}
+
/*
* Migrate pages from one node to a target node.
* Returns error or the number of pages not migrated.
@@ -616,6 +626,10 @@ int migrate_to_node(struct mm_struct *mm
if (!list_empty(&pagelist))
err = migrate_pages(&pagelist, new_node_page, dest);

+ if (!err)
+ err = migrate_page_tables_mm(mm, source,
+ new_node_page_page_tables, dest);
+
return err;
}

diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/mm/migrate.c 2.6.23a/mm/migrate.c
--- 2.6.23/mm/migrate.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/mm/migrate.c 2008-01-17 07:37:21.000000000 -0800
@@ -28,9 +28,15 @@
#include <linux/mempolicy.h>
#include <linux/vmalloc.h>
#include <linux/security.h>
-
+#include <linux/mm.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/pgalloc.h>
#include "internal.h"

+int migrate_page_tables_mm(struct mm_struct *mm, int source,
+ new_page_t get_new_page, unsigned long private);
+
#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))

/*
@@ -158,6 +164,7 @@ static void remove_migration_pte(struct

ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
+ delimbo_pte(&ptep, &ptl, &pmd, mm, addr);
pte = *ptep;
if (!is_swap_pte(pte))
goto out;
@@ -859,9 +866,10 @@ set_status:
err = migrate_pages(&pagelist, new_page_node,
(unsigned long)pm);
else
- err = -ENOENT;
+ err = 0;

up_read(&mm->mmap_sem);
+
return err;
}

@@ -1039,3 +1047,312 @@ int migrate_vmas(struct mm_struct *mm, c
}
return err;
}
+
+static void rcu_free_pt(struct rcu_head *head)
+{
+ /* Need to know that the mm has been flushed before
+ * we get here. Otherwise we need a way to find
+ * the appropriate mm to flush.
+ */
+ struct page *page = container_of(head, struct page, rcu);
+ __free_page(page);
+}
+
+int migrate_pgd(pgd_t *pgd, struct mm_struct *mm,
+ unsigned long addr, struct page *dest,
+ struct list_head *old_pages)
+{
+ unsigned long flags;
+ void *dest_ptr;
+ pud_t *pud;
+
+ spin_lock_irqsave(&mm->page_table_lock, flags);
+
+ delimbo_pgd(&pgd, mm, addr);
+
+ pud = pud_offset(pgd, addr);
+ dest_ptr = page_address(dest);
+ memcpy(dest_ptr, pud, PAGE_SIZE);
+
+ list_add_tail(&(pgd_page(*pgd)->lru), old_pages);
+ pgd_populate(mm, pgd, dest_ptr);
+
+ flush_tlb_pgtables(mm, addr,
+ addr + (1 << PMD_SHIFT)
+ - 1);
+
+ maybe_need_flush_mm(mm);
+
+ spin_unlock_irqrestore(&mm->page_table_lock, flags);
+
+ return 0;
+
+}
+
+int migrate_pud(pud_t *pud, struct mm_struct *mm, unsigned long addr,
+ struct page *dest, struct list_head *old_pages)
+{
+ unsigned long flags;
+ void *dest_ptr;
+ pmd_t *pmd;
+
+ spin_lock_irqsave(&mm->page_table_lock, flags);
+
+ delimbo_pud(&pud, mm, addr);
+ pmd = pmd_offset(pud, addr);
+
+ dest_ptr = page_address(dest);
+ memcpy(dest_ptr, pmd, PAGE_SIZE);
+
+ list_add_tail(&(pud_page(*pud)->lru), old_pages);
+
+ pud_populate(mm, pud, dest_ptr);
+ flush_tlb_pgtables(mm, addr,
+ addr + (1 << PMD_SHIFT)
+ - 1);
+ maybe_need_flush_mm(mm);
+
+ spin_unlock_irqrestore(&mm->page_table_lock, flags);
+
+ return 0;
+}
+
+
+int migrate_pmd(pmd_t *pmd, struct mm_struct *mm, unsigned long addr,
+ struct page *dest, struct list_head *old_pages)
+{
+ unsigned long flags;
+ void *dest_ptr;
+ spinlock_t *ptl;
+ pte_t *pte;
+
+ spin_lock_irqsave(&mm->page_table_lock, flags);
+
+ delimbo_pmd(&pmd, mm, addr);
+
+ /* this could happen if the page table has been swapped out and we
+ were looking at the old one. */
+ if (unlikely(!pmd_present(*pmd))) {
+ spin_unlock_irqrestore(&mm->page_table_lock, flags);
+ return 1;
+ }
+
+ ptl = pte_lockptr(mm, pmd);
+
+ /* We need the page lock as well. */
+ if (ptl != &mm->page_table_lock)
+ spin_lock(ptl);
+
+ pte = pte_offset_map(pmd, addr);
+
+ dest_ptr = kmap_atomic(dest, KM_USER0);
+ memcpy(dest_ptr, pte, PAGE_SIZE);
+ list_add_tail(&(pmd_page(*pmd)->lru), old_pages);
+
+ kunmap_atomic(dest, KM_USER0);
+ pte_unmap(pte);
+ pte_lock_init(dest);
+ pmd_populate(NULL, pmd, dest);
+ flush_tlb_pgtables(mm, addr,
+ addr + (1 << PMD_SHIFT)
+ - 1);
+ maybe_need_flush_mm(mm);
+
+ if (ptl != &mm->page_table_lock)
+ spin_unlock(ptl);
+
+ spin_unlock_irqrestore(&mm->page_table_lock, flags);
+
+ return 0;
+}
+
+static int migrate_page_tables_pmd(pmd_t *pmd, struct mm_struct *mm,
+ unsigned long *address, int source,
+ new_page_t get_new_page,
+ unsigned long private,
+ struct list_head *old_pages)
+{
+ int pages_not_migrated = 0;
+ int *result = NULL;
+ struct page *old_page = virt_to_page(pmd);
+ struct page *new_page;
+ int not_migrated;
+
+ if (!pmd_present(*pmd)) {
+ *address += (unsigned long)PTRS_PER_PTE * PAGE_SIZE;
+ return 0;
+ }
+
+ if (page_to_nid(old_page) == source) {
+ new_page = get_new_page(old_page, private, &result);
+ if (!new_page)
+ return -ENOMEM;
+ not_migrated = migrate_pmd(pmd, mm, *address, new_page,
+ old_pages);
+ if (not_migrated)
+ __free_page(new_page);
+
+ pages_not_migrated += not_migrated;
+ }
+ *address += (unsigned long)PTRS_PER_PTE * PAGE_SIZE;
+
+ return pages_not_migrated;
+}
+
+static int migrate_page_tables_pud(pud_t *pud, struct mm_struct *mm,
+ unsigned long *address, int source,
+ new_page_t get_new_page,
+ unsigned long private,
+ struct list_head *old_pages)
+{
+ int pages_not_migrated = 0;
+ int i;
+ int *result = NULL;
+ struct page *old_page = virt_to_page(pud);
+ struct page *new_page;
+ int not_migrated;
+
+ if (!pud_present(*pud)) {
+ *address += (unsigned long)PTRS_PER_PMD *
+ (unsigned long)PTRS_PER_PTE * PAGE_SIZE;
+ return 0;
+ }
+
+ if (page_to_nid(old_page) == source) {
+ new_page = get_new_page(old_page, private, &result);
+ if (!new_page)
+ return -ENOMEM;
+
+ not_migrated = migrate_pud(pud, mm, *address, new_page,
+ old_pages);
+
+ if (not_migrated)
+ __free_page(new_page);
+
+ pages_not_migrated += not_migrated;
+ }
+
+ for (i = 0; i < PTRS_PER_PUD; i++) {
+ int ret;
+ ret = migrate_page_tables_pmd(pmd_offset(pud, *address), mm,
+ address, source,
+ get_new_page, private,
+ old_pages);
+ if (ret < 0)
+ return ret;
+ pages_not_migrated += ret;
+ }
+
+ return pages_not_migrated;
+}
+
+static int migrate_page_tables_pgd(pgd_t *pgd, struct mm_struct *mm,
+ unsigned long *address, int source,
+ new_page_t get_new_page,
+ unsigned long private,
+ struct list_head *old_pages)
+{
+ int pages_not_migrated = 0;
+ int i;
+ int *result = NULL;
+ struct page *old_page = virt_to_page(pgd);
+ struct page *new_page;
+ int not_migrated;
+
+ if (!pgd_present(*pgd)) {
+ *address += (unsigned long)PTRS_PER_PUD *
+ (unsigned long)PTRS_PER_PMD *
+ (unsigned long)PTRS_PER_PTE * PAGE_SIZE;
+ return 0;
+ }
+
+ if (page_to_nid(old_page) == source) {
+ new_page = get_new_page(old_page, private, &result);
+ if (!new_page)
+ return -ENOMEM;
+
+ not_migrated = migrate_pgd(pgd, mm, *address, new_page,
+ old_pages);
+ if (not_migrated)
+ __free_page(new_page);
+
+ pages_not_migrated += not_migrated;
+
+ }
+ for (i = 0; i < PTRS_PER_PUD; i++) {
+ int ret;
+ ret = migrate_page_tables_pud(pud_offset(pgd, *address), mm,
+ address, source,
+ get_new_page, private,
+ old_pages);
+ if (ret < 0)
+ return ret;
+ pages_not_migrated += ret;
+ }
+ return pages_not_migrated;
+}
+
+/* similiar to migrate pages, but migrates the page tables. */
+int migrate_page_tables_mm(struct mm_struct *mm, int source,
+ new_page_t get_new_page, unsigned long private)
+{
+ int pages_not_migrated = 0;
+ int i;
+ int *result = NULL;
+ struct page *old_page = virt_to_page(mm->pgd);
+ struct page *new_page;
+ unsigned long address = 0UL;
+ int not_migrated;
+ LIST_HEAD(old_pages);
+
+ if (mm->pgd == NULL)
+ return 0;
+
+ for (i = 0; i < PTRS_PER_PGD && address < mm->task_size; i++) {
+ int ret;
+ ret = migrate_page_tables_pgd(pgd_offset(mm, address), mm,
+ &address, source,
+ get_new_page, private,
+ &old_pages);
+ if (ret < 0)
+ return ret;
+
+ pages_not_migrated += ret;
+ }
+
+ if (page_to_nid(old_page) == source) {
+ new_page = get_new_page(old_page, private, &result);
+ if (!new_page)
+ return -ENOMEM;
+
+ not_migrated = migrate_top_level_page_table(mm, new_page,
+ &old_pages);
+ if (not_migrated)
+ __free_page(new_page);
+
+ pages_not_migrated += not_migrated;
+ }
+
+ /* reload or flush the tlbs if necessary. */
+ maybe_reload_tlb_mm(mm);
+
+ /* Add the pages freed up to the rcu list to be freed later.
+ * We need to do this after we flush the mm to prevent
+ * a possible race where the page is freed while one of
+ * the cpus is still looking at it.
+ */
+
+ while (!list_empty(&old_pages)) {
+ old_page = list_first_entry(&old_pages, struct page, lru);
+ list_del(&old_page->lru);
+ /* This is the same memory as the list
+ * head we are using to maintain the list.
+ * so we have to make sure the list_del
+ * comes first.
+ */
+ INIT_RCU_HEAD(&old_page->rcu);
+ call_rcu(&old_page->rcu, rcu_free_pt);
+ }
+
+ return pages_not_migrated;
+}
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/mm/mremap.c 2.6.23a/mm/mremap.c
--- 2.6.23/mm/mremap.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/mm/mremap.c 2007-10-30 06:57:49.000000000 -0700
@@ -98,6 +98,7 @@ static void move_ptes(struct vm_area_str
new_ptl = pte_lockptr(mm, new_pmd);
if (new_ptl != old_ptl)
spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
+ delimbo_pte(&new_pte, &new_ptl, &new_pmd, mm, new_addr);
arch_enter_lazy_mmu_mode();

for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
diff -uprwNbB -X 2.6.23/Documentation/dontdiff 2.6.23/mm/rmap.c 2.6.23a/mm/rmap.c
--- 2.6.23/mm/rmap.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/mm/rmap.c 2007-10-29 09:46:25.000000000 -0700
@@ -254,6 +254,7 @@ pte_t *page_check_address(struct page *p

ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
+ delimbo_pte(&pte, &ptl, &pmd, mm, address);
if (pte_present(*pte) && page_to_pfn(page) == pte_pfn(*pte)) {
*ptlp = ptl;
return pte;
--
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