Messages in this thread |  | | Date | Tue, 9 Jan 2001 12:28:10 +0100 | From | Christoph Hellwig <> | Subject | Re: [PLEASE-TESTME] Zerocopy networking patch, 2.4.0-1 |
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On Tue, Jan 09, 2001 at 02:31:13AM -0800, David S. Miller wrote: > Date: Tue, 9 Jan 2001 11:31:45 +0100 > From: Christoph Hellwig <hch@caldera.de> > > Yuck. A new file_opo just to get a few benchmarks right ... I > hope the writepages stuff will not be merged in Linus tree (but I > wish the code behind it!) > > It's a "I know how to send a page somewhere via this filedescriptor > all by myself" operation. I don't see why people need to take > painkillers over this for 2.4.x. I think f_op->write is stupid, such > a special case file operation just to get a few benchmarks right. > This is the kind of argument I am hearing. > > Orthogonal to f_op->write being for specifying a low-level > implementation of sys_write, f_op->writepage is for specifying a > low-level implementation of sys_sendfile. Can you grok that?
Sure. But sendfile is not one of the fundamental UNIX operations... If there was no alternative to this I would probably have not said anything, but with the rw_kiovec file op just before the door I don't see any reason to add this _very_ specific file operation.
An alloc_kiovec before and an free_kiovec after the actual call and the memory overhaed of a kiobuf won't hurt so much that it stands against a clean interface, IMHO.
> > Linus has already seen this. Originally he had a gripe because in an > older revision of the code used to allow multiple pages to be passed > in an array to the writepage(s) operation. He didn't like that, so I > made it take only one page as he requested. He had no other major > objections to the infrastructure.
You get that multiple page call with kiobufs for free...
Christoph
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