On 08/03/2016 09:58 AM, Baoquan He wrote: > On 08/03/16 at 08:59am, Zhou Wenjian wrote: >> SMP dump-capture kernel is useful to improve the performance of kdump in >> some cases. So add the description of bringing up SMP dump-capture kernel. >> >> Signed-off-by: Zhou Wenjian <zhouwj-fnst at cn.fujitsu.com> >> --- >> Documentation/kdump/kdump.txt | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt >> index 4aa194e..948b42d 100644 >> --- a/Documentation/kdump/kdump.txt >> +++ b/Documentation/kdump/kdump.txt >> @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel: >> Note, though maxcpus always works, we should replace it by nr_cpus to >> save memory if supported by the current ARCH, such as x86. >> >> +* We should bring up a SMP dump-capture kernel if we intend to use > > Well, here about SMP dump-capture kernel do you mean kdump kernel with > multi-cpu? If I understand it correctly, it's still SMP kdump kernel > though nr_cpus=1 is specified. > Actually, I haven't know the detail about it. I wrote the sentence almost based on the original description: * We generally don' have to bring up a SMP kernel just to capture the dump. Hence generally it is useful either to build a UP dump-capture kernel or specify maxcpus=1 option while loading dump-capture kernel. >> + multi-threads programs with it, such as parallel dump feature of >> + makedumpfile. Otherwise, the multi-threads program may have a great >> + performance degradation. To bring up a SMP dump-capture kernel, we >> + should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while >> + loading it. >> + >> * For s390x there are two kdump modes: If a ELF header is specified with >> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it >> is done on all other architectures. If no elfcorehdr= kernel parameter is >> -- >> 1.8.3.1 >> >> >> >> >> _______________________________________________ >> kexec mailing list >> kexec at lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/kexec > > -- Thanks Zhou
