> From: Peter Zijlstra [mailto:peterz@xxxxxxxxxxxxx] > On Mon, Aug 31, 2015 at 08:53:11AM +0000, 河合英宏 / KAWAI，HIDEHIRO wrote: > > > I understand your question. I don't intend to permit the recursive > > > call of crash_kexec() as for 'old_cpu != this_cpu' check. That is > > > needed for the case of panic() --> crash_kexec(). Since panic_cpu has > > > already been set to this_cpu in panic() (please see PATCH 1/4), no one > > > can run crash_kexec() without 'old_cpu != this_cpu' check. > > > > > > If you don't like this check, I would also be able to handle this case > > > like below: > > > > > > crash_kexec() > > > { > > > old_cpu = atomic_cmpxchg(&panic_cpu, -1, this_cpu); > > > if (old_cpu != -1) > > > return; > > > > > > __crash_kexec(); > > > } > > > > > > panic() > > > { > > > atomic_cmpxchg(&panic_cpu, -1, this_cpu); > > > __crash_kexec(); > > > ... > > > > > > > Is that OK? > > I suppose so, but I think me getting confused means comments can be > added/improved. OK, I'll improve comments and description in the next version. Thanks! Hidehiro Kawai Hitachi, Ltd. Research & Development Group ��.n��������+%������w��{.n�����{����* jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
