Messages in this thread | | | Date | Tue, 30 Mar 2004 16:47:47 -0500 | From | Jeff Garzik <> | Subject | Re: "Enhanced" MD code avaible for review |
| |
Justin T. Gibbs wrote: >>>That's unfortunate for those using ATA. A command submitted from userland >> >>Required, since one cannot know the data phase of vendor-specific commands. > > > So you are saying that this presents an unrecoverable situation?
No, I'm saying that the data phase need not have a bunch of in-kernel checks, it should be generated correctly from the source.
>>Particularly, checking whether the kernel is doing something wrong, or wrong, >>just wastes cycles. That's not a scalable way to code... if every driver >>and Linux subsystem did that, things would be unbearable slow. > > > Hmm. I've never had someone tell me that my SCSI drivers are slow.
This would be noticed in the CPU utilization area. Your drivers are probably a long way from being CPU-bound.
> I don't think that your statement is true in the general case. My > belief is that validation should occur where it is cheap and efficient > to do so. More expensive checks should be pushed into diagnostic code > that is disabled by default, but the code *should be there*. In any event, > for RAID meta-data, we're talking about code that is *not* in the common > or time critical path of the kernel. A few dozen lines of validation code > there has almost no impact on the size of the kernel and yields huge > benefits for debugging and maintaining the code. This is even more > the case in Linux the end user is often your test lab.
It doesn't scale terribly well, because the checks themselves become a source of bugs.
Jeff
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |