There is nice kernel helper to escape a given strings by provided rules. Let's
use it instead of custom approach.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[bfields@redhat.com: fix length calculation]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
...move the WARN_ON_ONCE inside the following if block since they use
the same condition.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
These were useful when I was tracking down a race condition between
svc_xprt_do_enqueue and svc_get_next_xprt.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Testing has shown that the pool->sp_lock can be a bottleneck on a busy
server. Every time data is received on a socket, the server must take
that lock in order to dequeue a thread from the sp_threads list.
Address this problem by eliminating the sp_threads list (which contains
threads that are currently idle) and replacing it with a RQ_BUSY flag in
svc_rqst. This allows us to walk the sp_all_threads list under the
rcu_read_lock and find a suitable thread for the xprt by doing a
test_and_set_bit.
Note that we do still have a potential atomicity problem however with
this approach. We don't want svc_xprt_do_enqueue to set the
rqst->rq_xprt pointer unless a test_and_set_bit of RQ_BUSY returned
zero (which indicates that the thread was idle). But, by the time we
check that, the bit could be flipped by a waking thread.
To address this, we acquire a new per-rqst spinlock (rq_lock) and take
that before doing the test_and_set_bit. If that returns false, then we
can set rq_xprt and drop the spinlock. Then, when the thread wakes up,
it must set the bit under the same spinlock and can trust that if it was
already set then the rq_xprt is also properly set.
With this scheme, the case where we have an idle thread no longer needs
to take the highly contended pool->sp_lock at all, and that removes the
bottleneck.
That still leaves one issue: What of the case where we walk the whole
sp_all_threads list and don't find an idle thread? Because the search is
lockess, it's possible for the queueing to race with a thread that is
going to sleep. To address that, we queue the xprt and then search again.
If we find an idle thread at that point, we can't attach the xprt to it
directly since that might race with a different thread waking up and
finding it. All we can do is wake the idle thread back up and let it
attempt to find the now-queued xprt.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Chris Worley <chris.worley@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
In a later patch, we'll be removing some spinlocking around the socket
and thread queueing code in order to fix some contention problems. At
that point, the stats counters will no longer be protected by the
sp_lock.
Change the counters to atomic_long_t fields, except for the
"sockets_queued" counter which will still be manipulated under a
spinlock.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Chris Worley <chris.worley@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Currently all svc_create callers pass in NULL for the shutdown parm,
which then gets fixed up to be svc_rpcb_cleanup if the service uses
rpcbind.
Simplify this by instead having the the only caller that requires it
(lockd) pass in svc_rpcb_cleanup and get rid of the special casing.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
The way that svc_wake_up works is a bit inefficient. It walks all of the
available pools for a service and either wakes up a task in each one or
sets the SP_TASK_PENDING flag in each one.
When svc_wake_up is called, there is no need to wake up more than one
thread to do this work. In practice, only lockd currently uses this
function and it's single threaded anyway. Thus, this just boils down to
doing a wake up of a thread in pool 0 or setting a single flag.
Eliminate the for loop in this function and change it to just operate on
pool 0. Also update the comments that sit above it and get rid of some
code that has been commented out for years now.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
In a later patch, we'll want to be able to handle this flag without
holding the sp_lock. Change this field to an unsigned long flags
field, and declare a new flag in it that can be managed with atomic
bitops.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
In a later patch, we're going to need some atomic bit flags. Since that
field will need to be an unsigned long, we mitigate that space
consumption by migrating some other bitflags to the new field. Start
with the rq_secure flag.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Mainly what I need is 860a0d9e51 "sunrpc: add some tracepoints in
svc_rqst handling functions", which subsequent server rpc patches from
jlayton depend on. I'm merging this later tag on the assumption that's
more likely to be a tested and stable point.
All it does is indicate whether a xprt has already been deleted from
a list or not, which is unnecessary since we use list_del_init and it's
always set and checked under the sv_lock anyway.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Add a new directory heirarchy under the debugfs sunrpc/ directory:
sunrpc/
rpc_xprt/
<xprt id>/
Within that directory, we can put files that give info about the
xprts. We do have the (minor) problem that there is no succinct,
unique identifier for rpc_xprts. So we generate them synthetically
with a static atomic_t counter.
For now, this directory just holds an "info" file, but we may add
other files to it in the future.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
It's possible to get a dump of the RPC task queue by writing a value to
/proc/sys/sunrpc/rpc_debug. If you write any value to that file, you get
a dump of the RPC client task list into the log buffer. This is a rather
inconvenient interface however, and makes it hard to get immediate info
about the task queue.
Add a new directory hierarchy under debugfs:
sunrpc/
rpc_clnt/
<clientid>/
Within each clientid directory we create a new "tasks" file that will
dump info similar to what shows up in the log buffer, but with a few
small differences -- we avoid printing raw kernel addresses in favor of
symbolic names and the XID is also displayed.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Pull NFS client RDMA changes for 3.19 from Anna Schumaker:
"NFS: Client side changes for RDMA
These patches various bugfixes and cleanups for using NFS over RDMA, including
better error handling and performance improvements by using pad optimization.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>"
* tag 'nfs-rdma-for-3.19' of git://git.linux-nfs.org/projects/anna/nfs-rdma:
xprtrdma: Display async errors
xprtrdma: Enable pad optimization
xprtrdma: Re-write rpcrdma_flush_cqs()
xprtrdma: Refactor tasklet scheduling
xprtrdma: unmap all FMRs during transport disconnect
xprtrdma: Cap req_cqinit
xprtrdma: Return an errno from rpcrdma_register_external()
Pull pull additional NFS client changes for 3.19 from Anna Schumaker:
"NFS: Generic client side changes from Chuck
These patches fixes for iostats and SETCLIENTID in addition to cleaning
up the nfs4_init_callback() function.
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>"
* tag 'nfs-cel-for-3.19' of git://git.linux-nfs.org/projects/anna/nfs-rdma:
NFS: Clean up nfs4_init_callback()
NFS: SETCLIENTID XDR buffer sizes are incorrect
SUNRPC: serialize iostats updates
Occasionally mountstats reports a negative retransmission rate.
Ensure that two RPCs completing concurrently don't confuse the sums
in the transport's op_metrics array.
Since pNFS filelayout can invoke rpc_count_iostats() on another
transport from xprt_release(), we can't rely on simply holding the
transport_lock in xprt_release(). There's nothing for it but hard
serialization. One spin lock per RPC operation should make this as
painless as it can be.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
An async error upcall is a hard error, and should be reported in
the system log.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
The Linux NFS/RDMA server used to reject NFSv3 WRITE requests when
pad optimization was enabled. That bug was fixed by commit
e560e3b510 ("svcrdma: Add zero padding if the client doesn't send
it").
We can now enable pad optimization on the client, which helps
performance and is supported now by both Linux and Solaris servers.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Currently rpcrdma_flush_cqs() attempts to avoid code duplication,
and simply invokes rpcrdma_recvcq_upcall and rpcrdma_sendcq_upcall.
1. rpcrdma_flush_cqs() can run concurrently with provider upcalls.
Both flush_cqs() and the upcalls were invoking ib_poll_cq() in
different threads using the same wc buffers (ep->rep_recv_wcs
and ep->rep_send_wcs), added by commit 1c00dd0776 ("xprtrmda:
Reduce calls to ib_poll_cq() in completion handlers").
During transport disconnect processing, this sometimes resulted
in the same reply getting added to the rpcrdma_tasklets_g list
more than once, which corrupted the list.
2. The upcall functions drain only a limited number of CQEs,
thanks to the poll budget added by commit 8301a2c047
("xprtrdma: Limit work done by completion handler").
Fixes: a7bc211ac9 ("xprtrdma: On disconnect, don't ignore ... ")
BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=276
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
