* Christoph Hellwig <[EMAIL PROTECTED]> wrote:
> Note that we also have a lot of inefficiency in the way we do deferred
> processing. Think of a setup where you run a XFS filesystem runs over
> a megaraid adapter.
>
> (1) we get a real hardirq, which just clears the interrupt and then
> deferes to a tasklet
> (2) tasklet walks the producer / consumer queue and then calls scsi_done
> for each completeted scsi command which ends up doing
> raise_softirq_irqoff(BLOCK_SOFTIRQ);
> (3) block softirq does the heavy lifting for command completion and finally
> calls back into the bio's completion routine
> (4) xfs wants to avoid irq safe locking and thus deferes the command to a
> kthread
i dont understand - why is a tasklet used at all? Why not do it straight
in the BLOCK_SOFTIRQ? Using tasklets there is extra, unnecessary
overhead already.
Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
