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. These patches are available in the for-next branch of: https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git Changes since v2: - Fix a cred use-after-free crasher - Fix a Smatch error reported by Dan Carpenter - Replace dereferences of nfsd_file::nf_inode - Further clean-ups and white-space adjustments Changes since RFC: - Fixed several crashers - Adjusted some of the new observability - Tests with generic/531 now pass - Fixed bugzilla 387 too, maybe - Plenty of clean-ups --- Chuck Lever (32): NFSD: Demote a WARN to a pr_warn() 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: 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: Replace the "init once" mechanism NFSD: Set up an rhashtable for the filecache NFSD: Convert the filecache to use rhashtable NFSD: Clean up unused code after rhashtable conversion NFSD: Separate tracepoints for acquire and create NFSD: Move nfsd_file_trace_alloc() tracepoint NFSD: Update the nfsd_file_fsnotify_handle_event() tracepoint NFSD: NFSv4 CLOSE should release an nfsd_file immediately NFSD: Ensure nf_inode is never dereferenced fs/nfsd/filecache.c | 727 ++++++++++++++++++++++++-------------- fs/nfsd/filecache.h | 7 +- fs/nfsd/nfs4proc.c | 6 +- fs/nfsd/nfs4state.c | 7 +- fs/nfsd/nfsctl.c | 10 + fs/nfsd/trace.h | 300 +++++++++++++--- include/trace/events/fs.h | 37 ++ 7 files changed, 774 insertions(+), 320 deletions(-) -- Chuck Lever
