Messages in this thread | | | Date | Fri, 16 Aug 2019 13:54:16 +0800 | From | Dave Young <> | Subject | Re: [RFC PATCH v4 9/9] printk: use a new ringbuffer implementation |
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On 08/16/19 at 01:46pm, Dave Young wrote: > John, can you cc kexec list for your later series? > > On 08/08/19 at 12:32am, John Ogness wrote: > > This is a major change because the API (and underlying workings) > > of the new ringbuffer are completely different than the previous > > ringbuffer. Since there are several components of the printk > > infrastructure that use the ringbuffer API (console, /dev/kmsg, > > syslog, kmsg_dump), there are quite a few changes throughout the > > printk implementation. > > > > This is also a conservative change because it continues to use the > > logbuf_lock raw spinlock even though the new ringbuffer is lockless. > > > > The externally visible changes are: > > > > 1. The exported vmcore info has changed: > > > > - VMCOREINFO_SYMBOL(log_buf); > > - VMCOREINFO_SYMBOL(log_buf_len); > > - VMCOREINFO_SYMBOL(log_first_idx); > > - VMCOREINFO_SYMBOL(clear_idx); > > - VMCOREINFO_SYMBOL(log_next_idx); > > + VMCOREINFO_SYMBOL(printk_rb_static); > > + VMCOREINFO_SYMBOL(printk_rb_dynamic); > > I assumed this needs some userspace work in kexec, how did you test > them? > > makedumpfile should need changes to dump the kernel log. > > Also kexec-tools includes a vmcore-dmesg.c to extrace dmesg from > /proc/vmcore. > > > > > 2. For the CONFIG_PPC_POWERNV powerpc platform, kernel log buffer > > registration is no longer available because there is no longer > > a single contigous block of memory to represent all of the > > ringbuffer. > > > > Signed-off-by: John Ogness <john.ogness@linutronix.de> > > --- > > arch/powerpc/platforms/powernv/opal.c | 22 +- > > include/linux/kmsg_dump.h | 6 +- > > include/linux/printk.h | 12 - > > kernel/printk/printk.c | 745 ++++++++++++++------------ > > kernel/printk/ringbuffer.h | 24 + > > 5 files changed, 415 insertions(+), 394 deletions(-) > >
[snip]
Seems kexec list has 40k limitation for msg body. Simon and David, maybe it is too small?
Thanks Dave
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