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authorJeff Layton <jlayton@primarydata.com>2014-10-23 08:01:02 -0400
committerJ. Bruce Fields <bfields@redhat.com>2014-11-07 16:56:11 -0500
commit5b095e99928cc13332d364f7cca7a9ca684369b4 (patch)
tree9e0c06472028d1caa9d9a36d297741a5edf7cf79 /fs/nfsd/state.h
parentb0cb9085239a20b7482ddd4839dd1d5476801dfa (diff)
downloadop-kernel-dev-5b095e99928cc13332d364f7cca7a9ca684369b4.zip
op-kernel-dev-5b095e99928cc13332d364f7cca7a9ca684369b4.tar.gz
nfsd: convert nfs4_file searches to use RCU
The global state_lock protects the file_hashtbl, and that has the potential to be a scalability bottleneck. Address this by making the file_hashtbl use RCU. Add a rcu_head to the nfs4_file and use that when freeing ones that have been hashed. In order to conserve space, we union the fi_rcu field with the fi_delegations list_head which must be clear by the time the last reference to the file is dropped. Convert find_file_locked to use RCU lookup primitives and not to require that the state_lock be held, and convert find_file to do a lockless lookup. Convert find_or_add_file to attempt a lockless lookup first, and then fall back to doing a locked search and insert if that fails to find anything. Also, minimize the number of times we need to calculate the hash value by passing it in as an argument to the search and insert functions, and optimize the order of arguments in nfsd4_init_file. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jeff Layton <jlayton@primarydata.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'fs/nfsd/state.h')
-rw-r--r--fs/nfsd/state.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 8e85e07..9d3be37 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -477,7 +477,10 @@ struct nfs4_file {
spinlock_t fi_lock;
struct hlist_node fi_hash; /* hash on fi_fhandle */
struct list_head fi_stateids;
- struct list_head fi_delegations;
+ union {
+ struct list_head fi_delegations;
+ struct rcu_head fi_rcu;
+ };
/* One each for O_RDONLY, O_WRONLY, O_RDWR: */
struct file * fi_fds[3];
/*
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