Low-level trace-buffers in CAM

[Pokala, Ravi]

-----Original Message-----


From: Ravi Pokala <rpokala at panasas.com>
Date: 2015-10-26, Monday at 21:21
To: Adrian Chadd <adrian.chadd at gmail.com>
Cc: "freebsd-geom at freebsd.org" <freebsd-geom at freebsd.org>, "freebsd-scsi at freebsd.org" <freebsd-scsi at freebsd.org>, "freebsd-hackers at freebsd.org" <freebsd-hackers at freebsd.org>, "ken at freebsd.org" <ken at freebsd.org>, "imp at freebsd.org" <imp at freebsd.org>, "scottl at freebsd.org" <scottl at freebsd.org>
Subject: Re: Low-level trace-buffers in CAM

>I'm having trouble parsing that - it's been a long day. You're talking about creating a generic in-kernel ring-buffer implementation, that we could leverage for (CAM tracing | KTR | whatever)? Like we did for various list and queue types in <sys/queue.h>? That's a good idea, but I go cross-eyed any time I look too closely at all the preprocessor-fu in there. :-)

Looking at it again today, I think I mis-parsed it. You were *actually* talking about a generic *interface* for passing a ring out of the kernel, right? The kernel just dumps onto it, and userland deals with walking it, figuring out if it's the record is something we're interested in, etc.

Or did you mean a 3rd thing? :-)

-Ravi