On 5/6/25 9:29 AM, Christoph Hellwig wrote: > On Mon, Apr 28, 2025 at 03:36:53PM -0400, cel@xxxxxxxxxx wrote: >> From: Chuck Lever <chuck.lever@xxxxxxxxxx> >> >> As a step towards making NFSD's maximum rsize and wsize variable at >> run-time, replace the fixed-size rq_vec[] array in struct svc_rqst >> with a chunk of dynamically-allocated memory. >> >> The rq_vec array is sized assuming request processing will need at >> most one kvec per page in a maximum-sized RPC message. >> >> On a system with 8-byte pointers and 4KB pages, pahole reports that >> the rq_vec[] array is 4144 bytes. This patch replaces that array >> with a single 8-byte pointer field. > > The right thing to do here is to kill this array. There is no > reason to use kvecs in the VFS read/write APIs these days, we can > use bio_vecs just fine, for which we have another allocation. Fair enough. That's a little more churn than I wanted to do in this patch series, but maybe it's easier than I expect. > And given that both are only used by the server and never the client > maybe they should both only be conditionally allocated? Not sure I follow you here. The client certainly does make extensive use of xdr_buf::bvec. -- Chuck Lever
