[kvm-devel] [PATCH 2 of 8] Moves all mmu notifier methods outside the PT lock (first and not last

[Andrea Arcangeli]

# HG changeset patch
# User Andrea Arcangeli [EMAIL PROTECTED]
# Date 1207159010 -7200
# Node ID fe00cb9deeb31467396370c835cb808f4b85209a
# Parent  a406c0cc686d0ca94a4d890d661cdfa48cfba09f
Moves all mmu notifier methods outside the PT lock (first and not last
step to make them sleep capable).

Signed-off-by: Andrea Arcangeli [EMAIL PROTECTED]

diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -121,27 +121,6 @@
seqlock_init(mm-mmu_notifier_lock);
 }
 
-#define ptep_clear_flush_notify(__vma, __address, __ptep)  \
-({ \
-   pte_t __pte;\
-   struct vm_area_struct *___vma = __vma;  \
-   unsigned long ___address = __address;   \
-   __pte = ptep_clear_flush(___vma, ___address, __ptep);   \
-   mmu_notifier_invalidate_page(___vma-vm_mm, ___address);\
-   __pte;  \
-})
-
-#define ptep_clear_flush_young_notify(__vma, __address, __ptep)
\
-({ \
-   int __young;\
-   struct vm_area_struct *___vma = __vma;  \
-   unsigned long ___address = __address;   \
-   __young = ptep_clear_flush_young(___vma, ___address, __ptep);   \
-   __young |= mmu_notifier_clear_flush_young(___vma-vm_mm,\
- ___address);  \
-   __young;\
-})
-
 #else /* CONFIG_MMU_NOTIFIER */
 
 static inline void mmu_notifier_release(struct mm_struct *mm)
@@ -173,9 +152,6 @@
 {
 }
 
-#define ptep_clear_flush_young_notify ptep_clear_flush_young
-#define ptep_clear_flush_notify ptep_clear_flush
-
 #endif /* CONFIG_MMU_NOTIFIER */
 
 #endif /* _LINUX_MMU_NOTIFIER_H */
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -194,11 +194,13 @@
if (pte) {
/* Nuke the page table entry. */
flush_cache_page(vma, address, pte_pfn(*pte));
-   pteval = ptep_clear_flush_notify(vma, address, pte);
+   pteval = ptep_clear_flush(vma, address, pte);
page_remove_rmap(page, vma);
dec_mm_counter(mm, file_rss);
BUG_ON(pte_dirty(pteval));
pte_unmap_unlock(pte, ptl);
+   /* must invalidate_page _before_ freeing the page */
+   mmu_notifier_invalidate_page(mm, address);
page_cache_release(page);
}
}
diff --git a/mm/memory.c b/mm/memory.c
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1626,9 +1626,10 @@
 */
page_table = pte_offset_map_lock(mm, pmd, address,
 ptl);
-   page_cache_release(old_page);
+   new_page = NULL;
if (!pte_same(*page_table, orig_pte))
goto unlock;
+   page_cache_release(old_page);
 
page_mkwrite = 1;
}
@@ -1644,6 +1645,7 @@
if (ptep_set_access_flags(vma, address, page_table, entry,1))
update_mmu_cache(vma, address, entry);
ret |= VM_FAULT_WRITE;
+   old_page = new_page = NULL;
goto unlock;
}
 
@@ -1688,7 +1690,7 @@
 * seen in the presence of one thread doing SMC and another
 * thread doing COW.
 */
-   ptep_clear_flush_notify(vma, address, page_table);
+   ptep_clear_flush(vma, address, page_table);
set_pte_at(mm, address, page_table, entry);
update_mmu_cache(vma, address, entry);
lru_cache_add_active(new_page);
@@ -1700,12 +1702,18 @@
} else
mem_cgroup_uncharge_page(new_page);
 
-   if (new_page)
+unlock:
+   pte_unmap_unlock(page_table, ptl);
+
+   if (new_page) {
+   if (new_page == old_page)
+   /* cow happened, notify before releasing old_page */
+   mmu_notifier_invalidate_page(mm, address);
page_cache_release(new_page);
+   }
if (old_page)
page_cache_release(old_page);
-unlock:
-   pte_unmap_unlock(page_table, ptl);
+
if (dirty_page) {
if (vma-vm_file)
file_update_time(vma-vm_file);
diff --git 

Re: [kvm-devel] [PATCH 2 of 8] Moves all mmu notifier methods outside the PT lock (first and not last

[Christoph Lameter]

On Wed, 2 Apr 2008, Andrea Arcangeli wrote:

 diff --git a/mm/memory.c b/mm/memory.c
 --- a/mm/memory.c
 +++ b/mm/memory.c
 @@ -1626,9 +1626,10 @@
*/
   page_table = pte_offset_map_lock(mm, pmd, address,
ptl);
 - page_cache_release(old_page);
 + new_page = NULL;
   if (!pte_same(*page_table, orig_pte))
   goto unlock;
 + page_cache_release(old_page);
  
   page_mkwrite = 1;
   }

This is deferring frees and not moving the callouts. KVM specific? What 
exactly is this doing?

A significant portion of this seems to be undoing what the first patch 
did.

-
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace
___
kvm-devel mailing list
kvm-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/kvm-devel