Re: [PATCH bpf-next 02/11] bpfilter: Add logging facility

On May 20, 2021, at 12:08 AM, Dmitrii Banshchikov [off-list ref] wrote:

On Wed, May 19, 2021 at 10:32:25AM -0700, Song Liu wrote:

quoted

On Tue, May 18, 2021 at 11:05 PM Dmitrii Banshchikov [off-list ref] wrote:

quoted

There are three logging levels for messages: FATAL, NOTICE and DEBUG.
When a message is logged with FATAL level it results in bpfilter
usermode helper termination.

Could you please explain why we choose to have 3 levels? Will we need
more levels,
like WARNING, ERROR, etc.?

I found that I need one level for development - to trace what
goes rignt and wrong. At the same time as those messages go to
dmesg this level is too verbose to be used under normal
circumstances. That is why another level is introduced. And the
last one exists to verify invariants or error condintions from
which there is no right way to recover and they result in
bpfilter termination.

/dev/kmsg supports specifying priority of the message. Like:

   echo '<4> This message have priority of 4' > /dev/kmsg

Therefore, with proper priority settings, we can have more levels safely.
Does this make sense?

Thanks,
Song

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