On (06/20/18 18:06), Sergey Senozhatsky wrote:
>
> b) printk_safe output is quite uncommon. And we flush per-CPU buffer
> from the same CPU which has caused printk_safe output [except for
> panic() flush] therefore logging the info available to log_store()
> seemed enough. IOW, once again, was a bit unsure if we want to add
> some complex code to already complex code, with just one potential
> user.
BTW, pr_cont() handling is not so simple when we are in printk_safe()
context. Unlike vprintk_emit() [normal printk], we don't use any
dedicated pr_cont() buffer in printk_safe. So, at a glance, I suspect
that injecting context info at every printk_safe_log_store() call for
`for (...) pr_cont()' loop is going to produce something like this:
I<10> 23 I<10> 43 I<10> 47 ....
// Hmm, maybe the line will endup having two prefixes. Once
// from printk_safe_log_store, the other from normal printk
// log_store().
While the same `for (...) pr_cont()' called from normal printk() context
will produce
I<10> 32 43 47 ....
It could be that I'm wrong.
Tetsuo, have you tested pr_cont() from printk_safe() context?
-ss
