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SubjectRe: [linux-usb-devel] System stalls using usb-storage
Date
Am Donnerstag, 24. Juli 2003 05:00 schrieb Matthew Dharm:
> Many people, including myself, have observed system stalls when using
> usb-storage. It happens when copying large amounts of data to a USB device
> -- everything (except the USB access) just stops for a little while. My
> best guess is that the block cache is filling up (easy since USB is so
> slow).

Can you do a vmstat run? That should provide conclusive data.
If so, write throteling is failing.

> The question is, what is the best way to handle this. I'm guessing that
> increasing the priority of the usb-storage control thread will help, but
> that's just a guess. I'm not even sure how to go about doing that, tho...

A kernel thread in the block io path has to have a higher priority than
any user task. Otherwise a priority inversion is possible.

Regards
Oliver

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