diff --git a/include/linux/pspace.h b/include/linux/pspace.h
new file mode 100644
index 0000000000000000000000000000000000000000..a8a064b0ad18fef8f424a8782536fa612c28ea9e
--- /dev/null
+++ b/include/linux/pspace.h
@@ -0,0 +1,16 @@
+#ifndef _LINUX_PSPACE_H
+#define _LINUX_PSPACE_H
+
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/threads.h>
+#include <linux/pid.h>
+
+struct pidmap {
+       atomic_t nr_free;
+       void *page;
+};
+
+#define PIDMAP_ENTRIES         ((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)
+
+#endif /* _LINUX_PSPACE_H */
diff --git a/kernel/pid.c b/kernel/pid.c
index 373639a10d8456dce5998d8c6f949569edb1abcb..8234bd08a3cb32d44a12f3efe865830443fa86b6 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -26,6 +26,7 @@
 #include <linux/init.h>
 #include <linux/bootmem.h>
 #include <linux/hash.h>
+#include <linux/pspace.h>
 
 #define pid_hashfn(nr) hash_long((unsigned long)nr, pidhash_shift)
 static struct hlist_head *pid_hash;
@@ -40,7 +41,6 @@ int last_pid;
 int pid_max_min = RESERVED_PIDS + 1;
 int pid_max_max = PID_MAX_LIMIT;
 
-#define PIDMAP_ENTRIES		((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)
 #define BITS_PER_PAGE		(PAGE_SIZE*8)
 #define BITS_PER_PAGE_MASK	(BITS_PER_PAGE-1)
 #define mk_pid(map, off)	(((map) - pidmap_array)*BITS_PER_PAGE + (off))
@@ -53,11 +53,6 @@ int pid_max_max = PID_MAX_LIMIT;
  * value does not cause lots of bitmaps to be allocated, but
  * the scheme scales to up to 4 million PIDs, runtime.
  */
-struct pidmap {
-	atomic_t nr_free;
-	void *page;
-};
-
 static struct pidmap pidmap_array[PIDMAP_ENTRIES] =
 	 { [ 0 ... PIDMAP_ENTRIES-1 ] = { ATOMIC_INIT(BITS_PER_PAGE), NULL } };