Messages in this thread | | | Date | Fri, 19 Dec 2008 20:38:04 +0300 | From | Vladislav Bolkhovitin <> | Subject | Re: [RFC]: Support for zero-copy TCP transmit of user space data |
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Andi Kleen, on 12/19/2008 02:27 PM wrote: > Vladislav Bolkhovitin <vst@vlnb.net> writes: >> - Although usage of struct page to keep network related pointer might >> look as a layering violation, it isn't. I wrote in >> http://lkml.org/lkml/2008/12/15/190 why. > > Sorry but extending struct page for this is really a bad idea because > of the extreme memory overhead even when it's not used (which is a > problem on distribution kernels) Find some other way to store this > information. Even for patches with more general value it was not > acceptable.
Sure, this is why I propose to disable that option by default in distribution kernels, so it would produce no harm. ISCSI-SCST can work in this configuration quite well too. People who need both iSCSI target *and* fast working user space device handlers would simply enable that option and rebuild the kernel. Rejecting this patch provides much worse alternative: those people would also have to *patch* the kernel at first, only then enable that option, then rebuild the kernel. (I'm repeating it to make sure you didn't miss this my point; it was in the part of my original message, which you cut out.)
Thanks, Vlad
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