[patch 2/6] mmu_notifier: Callbacks to invalidate address ranges

From: Christoph Lameter
Date: Fri Feb 15 2008 - 01:52:29 EST

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The invalidation of address ranges in a mm_struct needs to be
performed when pages are removed or permissions etc change.

If invalidate_range_begin() is called with locks held then we
pass a flag into invalidate_range() to indicate that no sleeping is
possible. Locks are only held for truncate and huge pages.

In two cases we use invalidate_range_begin/end to invalidate
single pages because the pair allows holding off new references
(idea by Robin Holt).

do_wp_page(): We hold off new references while we update the pte.

xip_unmap: We are not taking the PageLock so we cannot
use the invalidate_page mmu_rmap_notifier. invalidate_range_begin/end
stands in.

Signed-off-by: Andrea Arcangeli <andrea@xxxxxxxxxxxx>
Signed-off-by: Robin Holt <holt@xxxxxxx>
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>

---
mm/filemap_xip.c | 5 +++++
mm/fremap.c | 3 +++
mm/hugetlb.c | 3 +++
mm/memory.c | 35 +++++++++++++++++++++++++++++------
mm/mmap.c | 2 ++
mm/mprotect.c | 3 +++
mm/mremap.c | 7 ++++++-
7 files changed, 51 insertions(+), 7 deletions(-)

Index: linux-2.6/mm/fremap.c
===================================================================
--- linux-2.6.orig/mm/fremap.c 2008-02-14 18:43:31.000000000 -0800
+++ linux-2.6/mm/fremap.c 2008-02-14 18:45:07.000000000 -0800
@@ -15,6 +15,7 @@
#include <linux/rmap.h>
#include <linux/module.h>
#include <linux/syscalls.h>
+#include <linux/mmu_notifier.h>

#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
@@ -214,7 +215,9 @@ asmlinkage long sys_remap_file_pages(uns
spin_unlock(&mapping->i_mmap_lock);
}

+ mmu_notifier(invalidate_range_begin, mm, start, start + size, 0);
err = populate_range(mm, vma, start, size, pgoff);
+ mmu_notifier(invalidate_range_end, mm, start, start + size, 0);
if (!err && !(flags & MAP_NONBLOCK)) {
if (unlikely(has_write_lock)) {
downgrade_write(&mm->mmap_sem);
Index: linux-2.6/mm/memory.c
===================================================================
--- linux-2.6.orig/mm/memory.c 2008-02-14 18:43:31.000000000 -0800
+++ linux-2.6/mm/memory.c 2008-02-14 18:45:07.000000000 -0800
@@ -51,6 +51,7 @@
#include <linux/init.h>
#include <linux/writeback.h>
#include <linux/memcontrol.h>
+#include <linux/mmu_notifier.h>

#include <asm/pgalloc.h>
#include <asm/uaccess.h>
@@ -611,6 +612,9 @@ int copy_page_range(struct mm_struct *ds
if (is_vm_hugetlb_page(vma))
return copy_hugetlb_page_range(dst_mm, src_mm, vma);

+ if (is_cow_mapping(vma->vm_flags))
+ mmu_notifier(invalidate_range_begin, src_mm, addr, end, 0);
+
dst_pgd = pgd_offset(dst_mm, addr);
src_pgd = pgd_offset(src_mm, addr);
do {
@@ -621,6 +625,11 @@ int copy_page_range(struct mm_struct *ds
vma, addr, next))
return -ENOMEM;
} while (dst_pgd++, src_pgd++, addr = next, addr != end);
+
+ if (is_cow_mapping(vma->vm_flags))
+ mmu_notifier(invalidate_range_end, src_mm,
+ vma->vm_start, end, 0);
+
return 0;
}

@@ -893,13 +902,16 @@ unsigned long zap_page_range(struct vm_a
struct mmu_gather *tlb;
unsigned long end = address + size;
unsigned long nr_accounted = 0;
+ int atomic = details ? (details->i_mmap_lock != 0) : 0;

lru_add_drain();
tlb = tlb_gather_mmu(mm, 0);
update_hiwater_rss(mm);
+ mmu_notifier(invalidate_range_begin, mm, address, end, atomic);
end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
if (tlb)
tlb_finish_mmu(tlb, address, end);
+ mmu_notifier(invalidate_range_end, mm, address, end, atomic);
return end;
}

@@ -1339,7 +1351,7 @@ int remap_pfn_range(struct vm_area_struc
{
pgd_t *pgd;
unsigned long next;
- unsigned long end = addr + PAGE_ALIGN(size);
+ unsigned long start = addr, end = addr + PAGE_ALIGN(size);
struct mm_struct *mm = vma->vm_mm;
int err;

@@ -1373,6 +1385,7 @@ int remap_pfn_range(struct vm_area_struc
pfn -= addr >> PAGE_SHIFT;
pgd = pgd_offset(mm, addr);
flush_cache_range(vma, addr, end);
+ mmu_notifier(invalidate_range_begin, mm, start, end, 0);
do {
next = pgd_addr_end(addr, end);
err = remap_pud_range(mm, pgd, addr, next,
@@ -1380,6 +1393,7 @@ int remap_pfn_range(struct vm_area_struc
if (err)
break;
} while (pgd++, addr = next, addr != end);
+ mmu_notifier(invalidate_range_end, mm, start, end, 0);
return err;
}
EXPORT_SYMBOL(remap_pfn_range);
@@ -1463,10 +1477,11 @@ int apply_to_page_range(struct mm_struct
{
pgd_t *pgd;
unsigned long next;
- unsigned long end = addr + size;
+ unsigned long start = addr, end = addr + size;
int err;

BUG_ON(addr >= end);
+ mmu_notifier(invalidate_range_begin, mm, start, end, 0);
pgd = pgd_offset(mm, addr);
do {
next = pgd_addr_end(addr, end);
@@ -1474,6 +1489,7 @@ int apply_to_page_range(struct mm_struct
if (err)
break;
} while (pgd++, addr = next, addr != end);
+ mmu_notifier(invalidate_range_end, mm, start, end, 0);
return err;
}
EXPORT_SYMBOL_GPL(apply_to_page_range);
@@ -1614,8 +1630,10 @@ static int do_wp_page(struct mm_struct *
page_table = pte_offset_map_lock(mm, pmd, address,
&ptl);
page_cache_release(old_page);
- if (!pte_same(*page_table, orig_pte))
- goto unlock;
+ if (!pte_same(*page_table, orig_pte)) {
+ pte_unmap_unlock(page_table, ptl);
+ goto check_dirty;
+ }

page_mkwrite = 1;
}
@@ -1631,7 +1649,8 @@ static int do_wp_page(struct mm_struct *
if (ptep_set_access_flags(vma, address, page_table, entry,1))
update_mmu_cache(vma, address, entry);
ret |= VM_FAULT_WRITE;
- goto unlock;
+ pte_unmap_unlock(page_table, ptl);
+ goto check_dirty;
}

/*
@@ -1653,6 +1672,8 @@ gotten:
if (mem_cgroup_charge(new_page, mm, GFP_KERNEL))
goto oom_free_new;

+ mmu_notifier(invalidate_range_begin, mm, address,
+ address + PAGE_SIZE, 0);
/*
* Re-check the pte - we dropped the lock
*/
@@ -1691,8 +1712,10 @@ gotten:
page_cache_release(new_page);
if (old_page)
page_cache_release(old_page);
-unlock:
pte_unmap_unlock(page_table, ptl);
+ mmu_notifier(invalidate_range_end, mm,
+ address, address + PAGE_SIZE, 0);
+check_dirty:
if (dirty_page) {
if (vma->vm_file)
file_update_time(vma->vm_file);
Index: linux-2.6/mm/mmap.c
===================================================================
--- linux-2.6.orig/mm/mmap.c 2008-02-14 18:44:56.000000000 -0800
+++ linux-2.6/mm/mmap.c 2008-02-14 18:45:07.000000000 -0800
@@ -1748,11 +1748,13 @@ static void unmap_region(struct mm_struc
lru_add_drain();
tlb = tlb_gather_mmu(mm, 0);
update_hiwater_rss(mm);
+ mmu_notifier(invalidate_range_begin, mm, start, end, 0);
unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
vm_unacct_memory(nr_accounted);
free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
next? next->vm_start: 0);
tlb_finish_mmu(tlb, start, end);
+ mmu_notifier(invalidate_range_end, mm, start, end, 0);
}

/*
Index: linux-2.6/mm/hugetlb.c
===================================================================
--- linux-2.6.orig/mm/hugetlb.c 2008-02-14 18:43:31.000000000 -0800
+++ linux-2.6/mm/hugetlb.c 2008-02-14 18:45:07.000000000 -0800
@@ -14,6 +14,7 @@
#include <linux/mempolicy.h>
#include <linux/cpuset.h>
#include <linux/mutex.h>
+#include <linux/mmu_notifier.h>

#include <asm/page.h>
#include <asm/pgtable.h>
@@ -755,6 +756,7 @@ void __unmap_hugepage_range(struct vm_ar
BUG_ON(start & ~HPAGE_MASK);
BUG_ON(end & ~HPAGE_MASK);

+ mmu_notifier(invalidate_range_begin, mm, start, end, 1);
spin_lock(&mm->page_table_lock);
for (address = start; address < end; address += HPAGE_SIZE) {
ptep = huge_pte_offset(mm, address);
@@ -775,6 +777,7 @@ void __unmap_hugepage_range(struct vm_ar
}
spin_unlock(&mm->page_table_lock);
flush_tlb_range(vma, start, end);
+ mmu_notifier(invalidate_range_end, mm, start, end, 1);
list_for_each_entry_safe(page, tmp, &page_list, lru) {
list_del(&page->lru);
put_page(page);
Index: linux-2.6/mm/filemap_xip.c
===================================================================
--- linux-2.6.orig/mm/filemap_xip.c 2008-02-14 18:43:31.000000000 -0800
+++ linux-2.6/mm/filemap_xip.c 2008-02-14 18:45:07.000000000 -0800
@@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/uio.h>
#include <linux/rmap.h>
+#include <linux/mmu_notifier.h>
#include <linux/sched.h>
#include <asm/tlbflush.h>

@@ -190,6 +191,8 @@ __xip_unmap (struct address_space * mapp
address = vma->vm_start +
((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
BUG_ON(address < vma->vm_start || address >= vma->vm_end);
+ mmu_notifier(invalidate_range_begin, mm, address,
+ address + PAGE_SIZE, 1);
pte = page_check_address(page, mm, address, &ptl);
if (pte) {
/* Nuke the page table entry. */
@@ -201,6 +204,8 @@ __xip_unmap (struct address_space * mapp
pte_unmap_unlock(pte, ptl);
page_cache_release(page);
}
+ mmu_notifier(invalidate_range_end, mm,
+ address, address + PAGE_SIZE, 1);
}
spin_unlock(&mapping->i_mmap_lock);
}
Index: linux-2.6/mm/mremap.c
===================================================================
--- linux-2.6.orig/mm/mremap.c 2008-02-14 18:43:31.000000000 -0800
+++ linux-2.6/mm/mremap.c 2008-02-14 18:45:07.000000000 -0800
@@ -18,6 +18,7 @@
#include <linux/highmem.h>
#include <linux/security.h>
#include <linux/syscalls.h>
+#include <linux/mmu_notifier.h>

#include <asm/uaccess.h>
#include <asm/cacheflush.h>
@@ -124,12 +125,15 @@ unsigned long move_page_tables(struct vm
unsigned long old_addr, struct vm_area_struct *new_vma,
unsigned long new_addr, unsigned long len)
{
- unsigned long extent, next, old_end;
+ unsigned long extent, next, old_start, old_end;
pmd_t *old_pmd, *new_pmd;

+ old_start = old_addr;
old_end = old_addr + len;
flush_cache_range(vma, old_addr, old_end);

+ mmu_notifier(invalidate_range_begin, vma->vm_mm,
+ old_addr, old_end, 0);
for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
cond_resched();
next = (old_addr + PMD_SIZE) & PMD_MASK;
@@ -150,6 +154,7 @@ unsigned long move_page_tables(struct vm
move_ptes(vma, old_pmd, old_addr, old_addr + extent,
new_vma, new_pmd, new_addr);
}
+ mmu_notifier(invalidate_range_end, vma->vm_mm, old_start, old_end, 0);

return len + old_addr - old_end; /* how much done */
}
Index: linux-2.6/mm/mprotect.c
===================================================================
--- linux-2.6.orig/mm/mprotect.c 2008-02-14 18:43:31.000000000 -0800
+++ linux-2.6/mm/mprotect.c 2008-02-14 18:45:07.000000000 -0800
@@ -21,6 +21,7 @@
#include <linux/syscalls.h>
#include <linux/swap.h>
#include <linux/swapops.h>
+#include <linux/mmu_notifier.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
@@ -198,10 +199,12 @@ success:
dirty_accountable = 1;
}

+ mmu_notifier(invalidate_range_begin, mm, start, end, 0);
if (is_vm_hugetlb_page(vma))
hugetlb_change_protection(vma, start, end, vma->vm_page_prot);
else
change_protection(vma, start, end, vma->vm_page_prot, dirty_accountable);
+ mmu_notifier(invalidate_range_end, mm, start, end, 0);
vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
vm_stat_account(mm, newflags, vma->vm_file, nrpages);
return 0;

--
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Next message: Andrew Morton: "Re: [PATCH 1/2] fb: add support for foreign endianness"
Previous message: Christoph Lameter: "[patch 5/6] mmu_notifier: Support for drivers with revers maps (f.e. for XPmem)"
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Next in thread: Andrew Morton: "Re: [patch 2/6] mmu_notifier: Callbacks to invalidate addressranges"
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