Ingo. Thank you, your reply. I will serch it again. On Tue, 16 Dec 2008 12:09:49 +0100 Ingo Molnar <mingo at elte.hu> wrote: > > * Yoshihiro Takahashi <ytakahashi at miraclelinux.com> wrote: > > > Hi. > > > > kdump hangs up by Sysrq+C trigger once in about 10 times in high load. > > After the above occurs, kdump cannot collect vmcores with NMI button. > > When waiting_for_crash_ipi does case more than 0, mdelay seem to make a > > stall. > > > > While nmi_shootdown_cpus(), mdelay may not work since interruption is > > disable. (ex. when crashing kernel by NMI interruption, all > > interruption may be disabled.). > > > > So I think that it should use other way (TSC) instead of mdelay() in > > nmi_shootdown_cpus(). > > mdelay uses either the tsc or CPU loops - neither stop while IRQs are > disabled. > > Could you figure out exactly why it hangs in your case? > > Ingo
