On Sat, 2018-10-20 at 00:11 +0200, Mkrtchyan, Tigran wrote: > Dear NFS fellows, > > we have notice a behavior of nfs client when iterating over a big > directory. The client re-requests entries that already has been. For > example, a client issues READDIR on a directory with 1k files. > Initial cookie > is 0, maxcount 32768. > > c -> s cookie 0 > s -> c last cookie 159 > c -> s cookie 105 > s -> c last cookie 259 > c -> s cookie 207 > > ... > > and so on. The interesting thing is, if I mount with rsize 8192 > (maxcount 8192), then first couple > or requests are asking for correct cookies - 0, 43, 81, 105. Again > 105 as with maxcount 32678. To > me it looks like that there is some kind of internal page (actually > NFS_MAX_READDIR_PAGES) alignment > and entries which do not fit into initially allocated PAGE_SIZE * > NFS_MAX_READDIR_PAGES memory > just get dropped. > > As 30% of each reply is thrown away, listing of large directories may > produce much more requests > than required. > > Is it an expected behavior? Yes. -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
