diff options
| author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-01-20 18:47:05 -0500 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2012-01-31 19:28:21 -0500 |
| commit | 4601df20fb3bf2b87e248abc622b8a7e4c3059fb (patch) | |
| tree | fc415ca673c8b4ced88941e0a11fb933da793c66 | |
| parent | 82b0a4c3c171b180629696e8d1d5f52516f711e6 (diff) | |
NFSv4: Avoid thundering herd issues with nfs_release_seqid
Store a pointer to the rpc_task in struct nfs_seqid so that we can wake up
only that request that is able to grab the lock after we've released it.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
| -rw-r--r-- | fs/nfs/nfs4_fs.h | 1 | ||||
| -rw-r--r-- | fs/nfs/nfs4state.c | 21 |
2 files changed, 16 insertions, 6 deletions
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index c45c21a5470f..b133b50dec9a 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -71,6 +71,7 @@ struct nfs_seqid_counter { struct nfs_seqid { struct nfs_seqid_counter *sequence; struct list_head list; + struct rpc_task *task; }; static inline void nfs_confirm_seqid(struct nfs_seqid_counter *seqid, int status) diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index f0e9881c2aa2..7d098604802c 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -916,20 +916,28 @@ struct nfs_seqid *nfs_alloc_seqid(struct nfs_seqid_counter *counter, gfp_t gfp_m if (new != NULL) { new->sequence = counter; INIT_LIST_HEAD(&new->list); + new->task = NULL; } return new; } void nfs_release_seqid(struct nfs_seqid *seqid) { - if (!list_empty(&seqid->list)) { - struct nfs_seqid_counter *sequence = seqid->sequence; + struct nfs_seqid_counter *sequence; - spin_lock(&sequence->lock); - list_del_init(&seqid->list); - spin_unlock(&sequence->lock); - rpc_wake_up(&sequence->wait); + if (list_empty(&seqid->list)) + return; + sequence = seqid->sequence; + spin_lock(&sequence->lock); + list_del_init(&seqid->list); + if (!list_empty(&sequence->list)) { + struct nfs_seqid *next; + + next = list_first_entry(&sequence->list, + struct nfs_seqid, list); + rpc_wake_up_queued_task(&sequence->wait, next->task); } + spin_unlock(&sequence->lock); } void nfs_free_seqid(struct nfs_seqid *seqid) @@ -1000,6 +1008,7 @@ int nfs_wait_on_sequence(struct nfs_seqid *seqid, struct rpc_task *task) int status = 0; spin_lock(&sequence->lock); + seqid->task = task; if (list_empty(&seqid->list)) list_add_tail(&seqid->list, &sequence->list); if (list_first_entry(&sequence->list, struct nfs_seqid, list) == seqid) |