From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wengang Date: Fri, 04 Apr 2014 09:26:17 +0800 Subject: [Ocfs2-devel] [PATCH] ocfs2: retry once dlm_dispatch_assert_master failed with ENOMEM In-Reply-To: <533D57F8.6010201@huawei.com> References: <533D57F8.6010201@huawei.com> Message-ID: <533E0A39.9020001@oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com O2net is using a single threaded work queue to process network requests. Blocking in a handler would block whole network processing. As you see, the memory allocation is with GFP_NOFS, if the first try failed, the following retries may still fail. Thus it could block a while which is not good. How about to limit the retries, say, 3 or 5 times. If it still failed to get memory, return an error to peer and peer decides to retry or give up. thanks, wengang ? 2014?04?03? 20:45, Joseph Qi ??: > Once dlm_dispatch_assert_master failed in dlm_master_requery_handler, > the only reason is ENOMEM. So just retry it instead of BUG(). > > Signed-off-by: Joseph Qi > --- > fs/ocfs2/dlm/dlmrecovery.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c > index 7035af0..f772d64 100644 > --- a/fs/ocfs2/dlm/dlmrecovery.c > +++ b/fs/ocfs2/dlm/dlmrecovery.c > @@ -1685,6 +1685,7 @@ int dlm_master_requery_handler(struct o2net_msg *msg, u32 len, void *data, > > hash = dlm_lockid_hash(req->name, req->namelen); > > +retry: > spin_lock(&dlm->spinlock); > res = __dlm_lookup_lockres(dlm, req->name, req->namelen, hash); > if (res) { > @@ -1693,10 +1694,14 @@ int dlm_master_requery_handler(struct o2net_msg *msg, u32 len, void *data, > if (master == dlm->node_num) { > int ret = dlm_dispatch_assert_master(dlm, res, > 0, 0, flags); > + /* ENOMEM returns, just retry */ > if (ret < 0) { > - mlog_errno(-ENOMEM); > - /* retry!? */ > - BUG(); > + spin_unlock(&res->spinlock); > + dlm_lockres_put(res); > + spin_unlock(&dlm->spinlock); > + mlog_errno(ret); > + msleep(50); > + goto retry; > } > } else /* put.. incase we are not the master */ > dlm_lockres_put(res);