From c46203acddd9b9200dbc53d0603c97355fd3a03b Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Fri, 8 Jul 2022 14:25:11 -0400 Subject: [PATCH] NFSD: Trace filecache LRU activity Observe the operation of garbage collection and the lifetime of filecache items. Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever --- fs/nfsd/filecache.c | 44 +++++++++++++++++++++++++++++++------------- fs/nfsd/trace.h | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 70 insertions(+), 13 deletions(-) diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c index f58685f..e831a7b 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -261,6 +261,18 @@ nfsd_file_flush(struct nfsd_file *nf) nfsd_reset_write_verifier(net_generic(nf->nf_net, nfsd_net_id)); } +static void nfsd_file_lru_add(struct nfsd_file *nf) +{ + if (list_lru_add(&nfsd_file_lru, &nf->nf_lru)) + trace_nfsd_file_lru_add(nf); +} + +static void nfsd_file_lru_remove(struct nfsd_file *nf) +{ + if (list_lru_del(&nfsd_file_lru, &nf->nf_lru)) + trace_nfsd_file_lru_del(nf); +} + static void nfsd_file_do_unhash(struct nfsd_file *nf) { @@ -280,8 +292,7 @@ nfsd_file_unhash(struct nfsd_file *nf) { if (test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { nfsd_file_do_unhash(nf); - if (!list_empty(&nf->nf_lru)) - list_lru_del(&nfsd_file_lru, &nf->nf_lru); + nfsd_file_lru_remove(nf); return true; } return false; @@ -444,27 +455,34 @@ nfsd_file_lru_cb(struct list_head *item, struct list_lru_one *lru, * counter. Here we check the counter and then test and clear the flag. * That order is deliberate to ensure that we can do this locklessly. */ - if (refcount_read(&nf->nf_ref) > 1) - goto out_skip; + if (refcount_read(&nf->nf_ref) > 1) { + trace_nfsd_file_gc_in_use(nf); + return LRU_SKIP; + } /* * Don't throw out files that are still undergoing I/O or * that have uncleared errors pending. */ - if (nfsd_file_check_writeback(nf)) - goto out_skip; + if (nfsd_file_check_writeback(nf)) { + trace_nfsd_file_gc_writeback(nf); + return LRU_SKIP; + } - if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags)) - goto out_skip; + if (test_and_clear_bit(NFSD_FILE_REFERENCED, &nf->nf_flags)) { + trace_nfsd_file_gc_referenced(nf); + return LRU_SKIP; + } - if (!test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) - goto out_skip; + if (!test_and_clear_bit(NFSD_FILE_HASHED, &nf->nf_flags)) { + trace_nfsd_file_gc_hashed(nf); + return LRU_SKIP; + } list_lru_isolate_move(lru, &nf->nf_lru, head); this_cpu_inc(nfsd_file_evictions); + trace_nfsd_file_gc_disposed(nf); return LRU_REMOVED; -out_skip: - return LRU_SKIP; } /* @@ -1017,7 +1035,7 @@ open_file: refcount_inc(&nf->nf_ref); __set_bit(NFSD_FILE_HASHED, &nf->nf_flags); __set_bit(NFSD_FILE_PENDING, &nf->nf_flags); - list_lru_add(&nfsd_file_lru, &nf->nf_lru); + nfsd_file_lru_add(nf); hlist_add_head_rcu(&nf->nf_node, &nfsd_file_hashtbl[hashval].nfb_head); ++nfsd_file_hashtbl[hashval].nfb_count; nfsd_file_hashtbl[hashval].nfb_maxcount = max(nfsd_file_hashtbl[hashval].nfb_maxcount, diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h index 22f57fe..64a6c57 100644 --- a/fs/nfsd/trace.h +++ b/fs/nfsd/trace.h @@ -895,6 +895,45 @@ TRACE_EVENT(nfsd_file_fsnotify_handle_event, __entry->nlink, __entry->mode, __entry->mask) ); +DECLARE_EVENT_CLASS(nfsd_file_gc_class, + TP_PROTO( + const struct nfsd_file *nf + ), + TP_ARGS(nf), + TP_STRUCT__entry( + __field(void *, nf_inode) + __field(void *, nf_file) + __field(int, nf_ref) + __field(unsigned long, nf_flags) + ), + TP_fast_assign( + __entry->nf_inode = nf->nf_inode; + __entry->nf_file = nf->nf_file; + __entry->nf_ref = refcount_read(&nf->nf_ref); + __entry->nf_flags = nf->nf_flags; + ), + TP_printk("inode=%p ref=%d nf_flags=%s nf_file=%p", + __entry->nf_inode, __entry->nf_ref, + show_nf_flags(__entry->nf_flags), + __entry->nf_file + ) +); + +#define DEFINE_NFSD_FILE_GC_EVENT(name) \ +DEFINE_EVENT(nfsd_file_gc_class, name, \ + TP_PROTO( \ + const struct nfsd_file *nf \ + ), \ + TP_ARGS(nf)) + +DEFINE_NFSD_FILE_GC_EVENT(nfsd_file_lru_add); +DEFINE_NFSD_FILE_GC_EVENT(nfsd_file_lru_del); +DEFINE_NFSD_FILE_GC_EVENT(nfsd_file_gc_in_use); +DEFINE_NFSD_FILE_GC_EVENT(nfsd_file_gc_writeback); +DEFINE_NFSD_FILE_GC_EVENT(nfsd_file_gc_referenced); +DEFINE_NFSD_FILE_GC_EVENT(nfsd_file_gc_hashed); +DEFINE_NFSD_FILE_GC_EVENT(nfsd_file_gc_disposed); + DECLARE_EVENT_CLASS(nfsd_file_lruwalk_class, TP_PROTO( unsigned long removed, -- 2.7.4