[PATCH] Avoiding mmap fragmentation

[linux-2.6] / arch / x86_64 / kernel / sys_x86_64.c

diff --git a/arch/x86_64/kernel/sys_x86_64.c b/arch/x86_64/kernel/sys_x86_64.c
index dbebd5ccba6b067531c0f7425d2bd17ef08c2bfd..cc7821c68851d5334b01359f8dd892a5266fdf0b 100644 (file)
--- a/arch/x86_64/kernel/sys_x86_64.c
+++ b/arch/x86_64/kernel/sys_x86_64.c
@@ -68,13 +68,7 @@ out:
 static void find_start_end(unsigned long flags, unsigned long *begin,
                           unsigned long *end)
 {
-#ifdef CONFIG_IA32_EMULATION
-       if (test_thread_flag(TIF_IA32)) { 
-               *begin = TASK_UNMAPPED_32;
-               *end = IA32_PAGE_OFFSET; 
-       } else 
-#endif
-       if (flags & MAP_32BIT) { 
+       if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
                /* This is usually used needed to map code in small
                   model, so it needs to be in the first 31bit. Limit
                   it to that.  This means we need to move the
@@ -84,10 +78,10 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
                   of playground for now. -AK */ 
                *begin = 0x40000000; 
                *end = 0x80000000;              
-       } else { 
-               *begin = TASK_UNMAPPED_64; 
+       } else {
+               *begin = TASK_UNMAPPED_BASE;
                *end = TASK_SIZE; 
-               }
+       }
 } 
 
 unsigned long
@@ -111,6 +105,11 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
                    (!vma || addr + len <= vma->vm_start))
                        return addr;
        }
+       if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
+           && len <= mm->cached_hole_size) {
+               mm->cached_hole_size = 0;
+               mm->free_area_cache = begin;
+       }
        addr = mm->free_area_cache;
        if (addr < begin) 
                addr = begin; 
@@ -126,6 +125,7 @@ full_search:
                         */
                        if (start_addr != begin) {
                                start_addr = addr = begin;
+                               mm->cached_hole_size = 0;
                                goto full_search;
                        }
                        return -ENOMEM;
@@ -137,6 +137,9 @@ 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;
        }
 }