On Wed, Jun 22, 2022 at 7:12 AM Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: > > This series overhauls the NFSD filecache, a cache of server-side > "struct file" objects recently used by NFS clients. The purposes of > this overhaul are an immediate improvement in cache scalability in > the number of open files, and preparation for further improvements. > > There are three categories of patches in this series: > > 1. Add observability of cache operation so we can see what we're > doing as changes are made to the code. > > 2. Improve the scalability of filecache garbage collection, > addressing several bugs along the way. > > 3. Improve the scalability of the filecache hash table by converting > it to use rhashtable. > > The series as it stands survives typical test workloads. Running > stress-tests like generic/531 is the next step. > > These patches are also available in the linux-nfs-bugzilla-386 > branch of > > https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git > > --- > > Chuck Lever (30): > NFSD: Report filecache LRU size > NFSD: Report count of calls to nfsd_file_acquire() > NFSD: Report count of freed filecache items > NFSD: Report average age of filecache items > NFSD: Add nfsd_file_lru_dispose_list() helper > NFSD: Refactor nfsd_file_gc() > NFSD: Refactor nfsd_file_lru_scan() > NFSD: Report the number of items evicted by the LRU walk > NFSD: Record number of flush calls > NFSD: Report filecache item construction failures > NFSD: Zero counters when the filecache is re-initialized > NFSD: Hook up the filecache stat file > NFSD: WARN when freeing an item still linked via nf_lru > NFSD: Trace filecache LRU activity > NFSD: Leave open files out of the filecache LRU > NFSD: Fix the filecache LRU shrinker > NFSD: Never call nfsd_file_gc() in foreground paths > NFSD: No longer record nf_hashval in the trace log > NFSD: Remove lockdep assertion from unhash_and_release_locked() > NFSD: nfsd_file_unhash can compute hashval from nf->nf_inode > NFSD: Refactor __nfsd_file_close_inode() > NFSD: nfsd_file_hash_remove can compute hashval > NFSD: Remove nfsd_file::nf_hashval > NFSD: Remove stale comment from nfsd_file_acquire() > NFSD: Clean up "open file" case in nfsd_file_acquire() > NFSD: Document nfsd_file_cache_purge() API contract > NFSD: Replace the "init once" mechanism > NFSD: Set up an rhashtable for the filecache > NFSD: Convert the filecache to use rhashtable > NFSD: Clean up unusued code after rhashtable conversion > > > fs/nfsd/filecache.c | 677 +++++++++++++++++++++++++++----------------- > fs/nfsd/filecache.h | 6 +- > fs/nfsd/nfsctl.c | 10 + > fs/nfsd/trace.h | 117 ++++++-- > 4 files changed, 522 insertions(+), 288 deletions(-) > > -- > Chuck Lever > Yep, looks good so far, thanks for doing this. Somewhat similar to my (buggy) attempt at fixing it that I sent at the time (don't put open files on the LRU, and use rhashtable), but cleaner and, presumably, less buggy :) Can't test it right now, but it seems like Wang already confirmed that it works. - Frank
