2 files changed, 41 insertions, 14 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index de54acd9942f..9da23c1ef9dc 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1175,7 +1175,12 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
                     (!vma || addr + len <= vma->vm_start))
                         return addr;
         }
-        start_addr = addr = mm->free_area_cache;
+        if (len > mm->cached_hole_size) {
+                start_addr = addr = mm->free_area_cache;
+        } else {
+                start_addr = addr = TASK_UNMAPPED_BASE;
+                mm->cached_hole_size = 0;
+        }
 
 full_search:
         for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
@@ -1186,7 +1191,9 @@ full_search:
                          * some holes.
                          */
                         if (start_addr != TASK_UNMAPPED_BASE) {
-                                start_addr = addr = TASK_UNMAPPED_BASE;
+                                addr = TASK_UNMAPPED_BASE;
+                                start_addr = addr;
+                                mm->cached_hole_size = 0;
                                 goto full_search;
                         }
                         return -ENOMEM;
@@ -1198,19 +1205,22 @@ full_search:
                         mm->free_area_cache = addr + len;
                         return addr;
                 }
+                if (addr + mm->cached_hole_size < vma->vm_start)
+                        mm->cached_hole_size = vma->vm_start - addr;
                 addr = vma->vm_end;
         }
 }
 #endif  
 
-void arch_unmap_area(struct vm_area_struct *area)
+void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
 {
         /*
          * Is this a new hole at the lowest possible address?
          */
-        if (area->vm_start >= TASK_UNMAPPED_BASE &&
-                        area->vm_start < area->vm_mm->free_area_cache)
-                area->vm_mm->free_area_cache = area->vm_start;
+        if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
+                mm->free_area_cache = addr;
+                mm->cached_hole_size = ~0UL;
+        }
 }
 
 /*
@@ -1240,6 +1250,12 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
                         return addr;
         }
 
+        /* check if free_area_cache is useful for us */
+        if (len <= mm->cached_hole_size) {
+                mm->cached_hole_size = 0;
+                mm->free_area_cache = mm->mmap_base;
+        }
+
         /* either no address requested or can't fit in requested address hole */
         addr = mm->free_area_cache;
 
@@ -1264,6 +1280,10 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
                         /* remember the address as a hint for next time */
                         return (mm->free_area_cache = addr);
 
+                /* remember the largest hole we saw so far */
+                if (addr + mm->cached_hole_size < vma->vm_start)
+                        mm->cached_hole_size = vma->vm_start - addr;
+
                 /* try just below the current vma->vm_start */
                 addr = vma->vm_start-len;
         } while (len < vma->vm_start);
@@ -1274,28 +1294,30 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
          * can happen with large stack limits and large mmap()
          * allocations.
          */
-        mm->free_area_cache = TASK_UNMAPPED_BASE;
+        mm->cached_hole_size = ~0UL;
+        mm->free_area_cache = TASK_UNMAPPED_BASE;
         addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
         /*
          * Restore the topdown base:
          */
         mm->free_area_cache = mm->mmap_base;
+        mm->cached_hole_size = ~0UL;
 
         return addr;
 }
 #endif
 
-void arch_unmap_area_topdown(struct vm_area_struct *area)
+void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
 {
         /*
          * Is this a new hole at the highest possible address?
          */
-        if (area->vm_end > area->vm_mm->free_area_cache)
-                area->vm_mm->free_area_cache = area->vm_end;
+        if (addr > mm->free_area_cache)
+                mm->free_area_cache = addr;
 
         /* dont allow allocations above current base */
-        if (area->vm_mm->free_area_cache > area->vm_mm->mmap_base)
-                area->vm_mm->free_area_cache = area->vm_mm->mmap_base;
+        if (mm->free_area_cache > mm->mmap_base)
+                mm->free_area_cache = mm->mmap_base;
 }
 
 unsigned long
@@ -1595,7 +1617,6 @@ static void unmap_vma(struct mm_struct *mm, struct vm_area_struct *area)
         if (area->vm_flags & VM_LOCKED)
                 area->vm_mm->locked_vm -= len >> PAGE_SHIFT;
         vm_stat_unaccount(area);
-        area->vm_mm->unmap_area(area);
         remove_vm_struct(area);
 }
 
@@ -1649,6 +1670,7 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
 {
         struct vm_area_struct **insertion_point;
         struct vm_area_struct *tail_vma = NULL;
+        unsigned long addr;
 
         insertion_point = (prev ? &prev->vm_next : &mm->mmap);
         do {
@@ -1659,6 +1681,11 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
         } while (vma && vma->vm_start < end);
         *insertion_point = vma;
         tail_vma->vm_next = NULL;
+        if (mm->unmap_area == arch_unmap_area)
+                addr = prev ? prev->vm_end : mm->mmap_base;
+        else
+                addr = vma ?  vma->vm_start : mm->mmap_base;
+        mm->unmap_area(mm, addr);
         mm->mmap_cache = NULL;          /* Kill the cache. */
 }
 
diff --git a/mm/nommu.c b/mm/nommu.c
index c53e9c8f6b4a..ce74452c02d9 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1067,7 +1067,7 @@ unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
         return -ENOMEM;
 }
 
-void arch_unmap_area(struct vm_area_struct *area)
+void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
 {
 }