On Fri, 2013-09-27 at 15:48 +0200, Peter Zijlstra wrote: > On Fri, Sep 27, 2013 at 06:44:55AM -0700, Joe Perches wrote: > > It's a CHK test, so it's only tested with --strict > > > > $ scripts/checkpatch.pl -f --strict kernel/mutex.c 2>&1 | grep memory > > CHECK: memory barrier without comment > > CHECK: memory barrier without comment > > > > It could be changed to WARN so it's always on. > > Yes please, we can't be too careful with memory barriers. I'll send the patch separately. It seems a pretty noisy test. There are 13 hits just in arch/x86/kernel/ $ ./scripts/checkpatch.pl -f arch/x86/kernel/*.c | grep -A3 "memory barrier" WARNING: memory barrier without comment #685: FILE: x86/kernel/alternative.c:685: + smp_wmb(); -- WARNING: memory barrier without comment #401: FILE: x86/kernel/kvm.c:401: + rmb(); WARNING: memory barrier without comment #403: FILE: x86/kernel/kvm.c:403: + rmb(); -- WARNING: memory barrier without comment #702: FILE: x86/kernel/kvm.c:702: + smp_wmb(); WARNING: memory barrier without comment #704: FILE: x86/kernel/kvm.c:704: + smp_wmb(); -- WARNING: memory barrier without comment #62: FILE: x86/kernel/ldt.c:62: + wmb(); WARNING: memory barrier without comment #64: FILE: x86/kernel/ldt.c:64: + wmb(); -- WARNING: memory barrier without comment #204: FILE: x86/kernel/smpboot.c:204: + wmb(); WARNING: memory barrier without comment #265: FILE: x86/kernel/smpboot.c:265: + wmb(); -- WARNING: memory barrier without comment #557: FILE: x86/kernel/smpboot.c:557: + mb(); -- WARNING: memory barrier without comment #1065: FILE: x86/kernel/smpboot.c:1065: + mb(); -- WARNING: memory barrier without comment #1321: FILE: x86/kernel/smpboot.c:1321: + mb(); WARNING: memory barrier without comment #1399: FILE: x86/kernel/smpboot.c:1399: + mb(); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>