On Tue, 21 Jul 2015 15:59:37 -0400 Eric B Munson [off-list ref] wrote:

With the refactored mlock code, introduce new system calls for mlock,
munlock, and munlockall.  The new calls will allow the user to specify
what lock states are being added or cleared.  mlock2 and munlock2 are
trivial at the moment, but a follow on patch will add a new mlock state
making them useful.

munlock2 addresses a limitation of the current implementation.  If a
user calls mlockall(MCL_CURRENT | MCL_FUTURE) and then later decides
that MCL_FUTURE should be removed, they would have to call munlockall()
followed by mlockall(MCL_CURRENT) which could potentially be very
expensive.  The new munlockall2 system call allows a user to simply
clear the MCL_FUTURE flag.

This is hard.  Maybe we shouldn't have wired up anything other than
x86.  That's what we usually do with new syscalls.

You appear to have missed
mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix.patch:

--- a/arch/arm64/include/asm/unistd.h~mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix
+++ a/arch/arm64/include/asm/unistd.h

@@ -44,7 +44,7 @@
 #define __ARM_NR_compat_cacheflush	(__ARM_NR_COMPAT_BASE+2)
 #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE+5)
 
-#define __NR_compat_syscalls		388
+#define __NR_compat_syscalls		391
 #endif
 
 #define __ARCH_WANT_SYS_CLONE

And mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix-2.patch:


From: Heiko Carstens <redacted>
Subject: mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix-2

can we just remove the s390 bits which cause the breakage?
I will wire up the syscalls as soon as the patch set gets merged.

Heiko Carstens [off-list ref]
Cc: Eric B Munson <redacted>
Cc: Stephen Rothwell <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/s390/kernel/syscalls.S |    3 ---
 1 file changed, 3 deletions(-)

diff -puN arch/s390/kernel/syscalls.S~mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix-2 arch/s390/kernel/syscalls.S

--- a/arch/s390/kernel/syscalls.S~mm-mlock-add-new-mlock-munlock-and-munlockall-system-calls-fix-2
+++ a/arch/s390/kernel/syscalls.S

@@ -363,6 +363,3 @@ SYSCALL(sys_bpf,compat_sys_bpf)
 SYSCALL(sys_s390_pci_mmio_write,compat_sys_s390_pci_mmio_write)
 SYSCALL(sys_s390_pci_mmio_read,compat_sys_s390_pci_mmio_read)
 SYSCALL(sys_execveat,compat_sys_execveat)
-SYSCALL(sys_mlock2,compat_sys_mlock2)			/* 355 */
-SYSCALL(sys_munlock2,compat_sys_munlock2)
-SYSCALL(sys_munlockall2,compat_sys_munlockall2)