On Sun, Jul 27, 2025 at 11:39:18AM -0400, Chuck Lever wrote: > On 7/24/25 3:30 PM, Mike Snitzer wrote: > > Hi, > > > > Some workloads benefit from NFSD avoiding the page cache, particularly > > those with a working set that is significantly larger than available > > system memory. This patchset introduces _optional_ support to > > configure the use of O_DIRECT or DONTCACHE for NFSD's READ and WRITE > > support. The NFSD default to use page cache is left unchanged. > > > > The performance win associated with using NFSD DIRECT was previously > > summarized here: > > https://lore.kernel.org/linux-nfs/aEslwqa9iMeZjjlV@xxxxxxxxxx/ > > This picture offers a nice summary of performance gains: > > https://original.art/NFSD_direct_vs_buffered_IO.jpg > > > > Similarly, NFS and LOCALIO in particular also benefit from avoiding > > the page cache for workloads that have a working set that is > > significantly larger than available system memory. Enter: NFS DIRECT, > > which makes it possible to always enable LOCALIO to use O_DIRECT even > > if the IO is not DIO-aligned. > > > > For this v5 I've combined the NFSD and NFSD patchsets because the NFS > > changes do depend on the the NFSD changes. In addition, I think it > > makes sense to review/test these changes together. > > I'm ready to pull the six NFSD patches in this series into nfsd-testing. > IMO we want regression and performance testing of NFSD, outside of the > LOCALIO paths, before claiming merge readiness. Makes sense, the NFSD changes are independent. LOCALIO's access to the dio alignment attrs in nfsd_file is a convenience. Mike
