On Mon, Nov 03, 2014 at 12:45:03AM +0000, Al Viro wrote: > > Note, BTW, that there's a damn good reason to convert the socket side of > things to iov_iter - as it is, ->splice_write() there is basically done with > page-by-page mapping and doing kernel_sendmsg(); being able to deal with > "map and copy" stuff *inside* ->sendmsg() would not only reduce the overhead, > it would allow to get rid of ->sendpage() completely. Basically, let > ->sendmsg() instances check the iov_iter type and play zerocopy games if > it's an "array of kernel pages" kind. Compare ->sendpage() and ->sendmsg() > instances for the protocols that have nontrivial ->sendpage(); you'll see > that there's a lot of duplication. Merging them looks very feasible, with > divergence happening only very deep in the call chain.
Honestly I don't really care which way we end up going as long as we pick one solution and stick with it. Right now we have an abomination in the form of skb_copy_datagram_const_iovec which is the worst of both worlds, plus it duplicates tons of code. So here's a few patches to kill this crap. Cheers, -- Email: Herbert Xu <herb...@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
