Re: [PATCH] usb: fix number of mapped SG DMA entries

[Sebastian Andrzej Siewior]

On 12/15/2011 05:01 PM, Alan Stern wrote:

> > Is there anything special you do to get into this kind of situation?
> > Like 16GiB of memory on 32bit with highmem and a brutal disk/io test
> > case so?
>
> As I understand it, the typical case is that two SG entries in a row
> refer to adjacent pages of physical memory.  The mapping routine then
> collapses them into a single entry referring to all the pages.
>
> However, this is not the sort of thing you can deliberately cause,
> unless you set up your SG list by hand.

Thanks, both of you for the explanation.

> Alan Stern

Sebastian
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