commit 
024914477e15ef8b17f271ec47f1bb8a589f0806 "memcg: move charges of anonymous
swap" revealed that the 1 byte and 2 byte cmpxchg is currently broken:
arch/s390/include/asm/system.h: Assembler messages:
arch/s390/include/asm/system.h:241: Error: junk at end of line: `(%r5)'
make[1]: *** [mm/page_cgroup.o] Error 1
make[1]: *** Waiting for unfinished jobs....
It turned out that commit 
987bcdacb18a3adc2a48d85c9b005069c2f4dd7b ([S390] use
inline assembly contraints available with gcc 3.3.3) broke the inline assembly.
The or operands are now in constraint 3 and 4 instead of 2 and 3.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
 
                        "       l       %0,%2\n"
                        "0:     nr      %0,%5\n"
                        "       lr      %1,%0\n"
-                       "       or      %0,%2\n"
-                       "       or      %1,%3\n"
+                       "       or      %0,%3\n"
+                       "       or      %1,%4\n"
                        "       cs      %0,%1,%2\n"
                        "       jnl     1f\n"
                        "       xr      %1,%0\n"
                        "       l       %0,%2\n"
                        "0:     nr      %0,%5\n"
                        "       lr      %1,%0\n"
-                       "       or      %0,%2\n"
-                       "       or      %1,%3\n"
+                       "       or      %0,%3\n"
+                       "       or      %1,%4\n"
                        "       cs      %0,%1,%2\n"
                        "       jnl     1f\n"
                        "       xr      %1,%0\n"