On Fri, Aug 10, 2018 at 02:07:37PM +0000, Ruhl, Michael J wrote: > >From: Jason Gunthorpe [mailto:jgg@xxxxxxxx] > >Sent: Thursday, August 9, 2018 10:15 PM > >To: linux-rdma@xxxxxxxxxxxxxxx; Leon Romanovsky <leonro@xxxxxxxxxxxx>; > >Guy Levi(SW) <guyle@xxxxxxxxxxxx>; Yishai Hadas > ><yishaih@xxxxxxxxxxxx>; Ruhl, Michael J <michael.j.ruhl@xxxxxxxxx> > >Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > >Subject: [PATCH v1 02/10] IB/uverbs: Build the specs into a radix tree at > >runtime > > > >From: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > > > >This radix tree datastructure is intended to replace the 'hash' structure > >used today for parsing ioctl methods during system calls. This first > >commit introduces the structure and builds it from the existing .rodata > >descriptions. > > > >The so-called hash arrangement is actually a 5 level open coded radix tree. > >This new version uses a 3 level radix tree built using the radix tree > >library. > > > >Overall this is much less code and much easier to build as the radix tree > >API allows for dynamic modification during the building. There is a small > >memory penalty to pay for this, but since the radix tree is allocated on > >a per device basis, a few kb of RAM seems immaterial considering the > >gained simplicity. > > > >The radix tree is similar to the existing tree, but also has a 'attr_bkey' > >concept, which is a small value'd index for each method attribute. This is > >used to simplify and improve performance of everything in the next > >patches. > > > >Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > >Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> > > > Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx> > > > One last question... :) > > Does uapi_finalize_ioctl_method() have to occur after all of the methods > have been added to the tree? It has to be done after the method is completed, which is only guaranteed after all the input specs have been integrated. Each spec can modify pre-existing methods. > Could it be done at the end of uapi_merge_method()? This would cause it to be run multiple times per method which wouldn't be very efficient.. Thanks, Jason
