From: Marcelo Ricardo Leitner > Sent: 08 December 2017 14:57 > > On Fri, Dec 08, 2017 at 02:06:04PM +0000, David Laight wrote: > > From: Xin Long > > > Sent: 08 December 2017 13:04 > > ... > > > @@ -264,8 +264,8 @@ struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, > > > frag |= SCTP_DATA_SACK_IMM; > > > } > > > > > > - chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, > > > - 0, GFP_KERNEL); > > > + chunk = asoc->stream.si->make_datafrag(asoc, sinfo, len, frag, > > > + GFP_KERNEL); > > > > I know that none of the sctp code is very optimised, but that indirect > > call is going to be horrid. > > Yeah.. but there is no way to avoid the double derreference > considering we only have the asoc pointer in there and we have to > reach the contents of the data chunk operations struct, and the .si > part is the same as 'stream' part as it's a constant offset. ... It isn't only the double indirect, the indirect call itself isn't 'fun'. I think there are other hot paths where you've replaced a sizeof() with a ?: clause. Caching the result might be much better. David -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
