Messages in this thread | | | Date | Wed, 07 Apr 2004 12:14:43 -0400 | From | Jeff Garzik <> | Subject | Re: cciss updates for 2.6.6xxx [1/2] |
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mikem@beardog.cca.cpqcorp.net wrote: > This patch adds per logical device queues to the HP cciss driver. It currently only implements a single lock but when time permits I will provide that funtionality. Thanks to Jeff Garzik for providing some sample code. > This patch built against 2.6.5. Please consider this for inclusion.
I appreciate the credit but I don't see that it addressed my original objection -- the starvation issue.
Do you cap the number of per-array requests a "1024 / n_arrays", or something like that? You mentioned that the hardware has a maximum of 1024 outstanding commands, for all devices. The two typical solutions are a round-robin queue (see carmel.c) or limiting each array such that if all arrays are full of commands, the total outstanding never exceeds 1024.
This patch may be OK for -mm, I would rather not see it go upstream -- it seems to me you are choosing to decrease stability to obtain a performance increase. I think you can increase performance without decreasing stability.
Jeff
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