Two changes:
- Show the number of SG entries that were mapped. This helps debug
DMA-related problems.
- Record the MR's resource ID instead of its memory address. This
groups each MR with its associated rdma-tool output, and reduces
needless exposure of memory addresses.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
On some platforms, DMA mapping part of a page is more costly than
copying bytes. Indeed, not involving the I/O MMU can help the
RPC/RDMA transport scale better for tiny I/Os across more RDMA
devices. This is because interaction with the I/O MMU is eliminated
for each of these small I/Os. Without the explicit unmapping, the
NIC no longer needs to do a costly internal TLB shoot down for
buffers that are just a handful of bytes.
Since pull-up is now a more a frequent operation, I've introduced a
trace point in the pull-up path. It can be used for debugging or
user-space tools that count pull-up frequency.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Performance optimization: Avoid syncing the transport buffer twice
when Reply buffer pull-up is necessary.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Same idea as the receive-side changes I did a while back: use
xdr_stream helpers rather than open-coding the XDR chunk list
encoders. This builds the Reply transport header from beginning to
end without backtracking.
As additional clean-ups, fill in documenting comments for the XDR
encoders and sprinkle some trace points in the new encoding
functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up. These are taken from the client-side RPC/RDMA transport
to a more global header file so they can be used elsewhere.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
These trace points are misnamed:
trace_svcrdma_encode_wseg
trace_svcrdma_encode_write
trace_svcrdma_encode_reply
trace_svcrdma_encode_rseg
trace_svcrdma_encode_read
trace_svcrdma_encode_pzr
Because they actually trace posting on the Send Queue. Let's rename
them so that I can add trace points in the chunk list encoders that
actually do trace chunk list encoding events.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Preparing for subsequent patches, no behavior change expected.
Pass the RPC Call's svc_rdma_recv_ctxt deeper into the sendto()
path. This enables passing more information about Requester-
provided Write and Reply chunks into those lower-level functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Preparing for subsequent patches, no behavior change expected.
Pass the RPC Call's svc_rdma_recv_ctxt deeper into the sendto()
path. This enables passing more information about Requester-
provided Write and Reply chunks into those lower-level functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Preparing for subsequent patches, no behavior change expected.
Pass the RPC Call's svc_rdma_recv_ctxt deeper into the sendto()
path. This enables passing more information about Requester-
provided Write and Reply chunks into the lower-level send
functions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cache the locations of the Requester-provided Write list and Reply
chunk so that the Send path doesn't need to parse the Call header
again.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The logic that checks incoming network headers has to be scrupulous.
De-duplicate: replace open-coded buffer overflow checks with the use
of xdr_stream helpers that are used most everywhere else XDR
decoding is done.
One minor change to the sanity checks: instead of checking the
length of individual segments, cap the length of the whole chunk
to be sure it can fit in the set of pages available in rq_pages.
This should be a better test of whether the server can handle the
chunks in each request.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Clean up. This trace point is no longer needed because the RDMA/core
CMA code has an equivalent trace point that was added by commit
ed999f820a ("RDMA/cma: Add trace points in RDMA Connection
Manager").
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Introduce a helper function to compute the XDR pad size of a
variable-length XDR object.
Clean up: Replace open-coded calculation of XDR pad sizes.
I'm sure I haven't found every instance of this calculation.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This error path is almost never executed. Found by code inspection.
Fixes: 99722fe4d5 ("svcrdma: Persistently allocate and DMA-map Send buffers")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
svcrdma expects that the payload falls precisely into the xdr_buf
page vector. This does not seem to be the case for
nfsd4_encode_readv().
This code is called only when fops->splice_read is missing or when
RQ_SPLICE_OK is clear, so it's not a noticeable problem in many
common cases.
Add new transport method: ->xpo_read_payload so that when a READ
payload does not fit exactly in rq_res's page vector, the XDR
encoder can inform the RPC transport exactly where that payload is,
without the payload's XDR pad.
That way, when a Write chunk is present, the transport knows what
byte range in the Reply message is supposed to be matched with the
chunk.
Note that the Linux NFS server implementation of NFS/RDMA can
currently handle only one Write chunk per RPC-over-RDMA message.
This simplifies the implementation of this fix.
Fixes: b042098063 ("nfsd4: allow exotic read compounds")
Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=198053
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
The @nents value that was passed to ib_dma_map_sg() has to be passed
to the matching ib_dma_unmap_sg() call. If ib_dma_map_sg() choses to
concatenate sg entries, it will return a different nents value than
it was passed.
The bug was exposed by recent changes to the AMD IOMMU driver, which
enabled sg entry concatenation.
Looking all the way back to commit 4143f34e01 ("xprtrdma: Port to
new memory registration API") and reviewing other kernel ULPs, it's
not clear that the frwr_map() logic was ever correct for this case.
Reported-by: Andre Tomt <andre@tomt.net>
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
To safely get rid of all rpcrdma_reps from a particular connection
instance, xprtrdma has to wait until each of those reps is finished
being used. A rep may be backing the rq_rcv_buf of an RPC that has
just completed, for example.
Since it is safe to invoke rpcrdma_rep_destroy() only in the Receive
completion handler, simply mark reps remaining in the rb_all_reps
list after the transport is drained. These will then be deleted as
rpcrdma_post_recvs pulls them off the rep free list.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This reduces the hardware and memory footprint of an unconnected
transport.
At some point in the future, transport reconnect will allow
resolving the destination IP address through a different device. The
current change enables reps for the new connection to be allocated
on whichever NUMA node the new device affines to after a reconnect.
Note that this does not destroy _all_ the transport's reps... there
will be a few that are still part of a running RPC completion.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Currently the underlying RDMA device is chosen at transport set-up
time. But it will soon be at connect time instead.
The maximum size of a transport header is based on device
capabilities. Thus transport header buffers have to be allocated
_after_ the underlying device has been chosen (via address and route
resolution); ie, in the connect worker.
Thus, move the allocation of transport header buffers to the connect
worker, after the point at which the underlying RDMA device has been
chosen.
This also means the RDMA device is available to do a DMA mapping of
these buffers at connect time, instead of in the hot I/O path. Make
that optimization as well.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Refactor: Perform the "is supported" check in rpcrdma_ep_create()
instead of in rpcrdma_ia_open(). frwr_open() is where most of the
logic to query device attributes is already located.
The current code displays a redundant error message when the device
does not support FRWR. As an additional clean-up, this patch removes
the extra message.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
To support device hotplug and migrating a connection between devices
of different capabilities, we have to guarantee that all in-kernel
devices can support the same max NFS payload size (1 megabyte).
This means that possibly one or two in-tree devices are no longer
supported for NFS/RDMA because they cannot support 1MB rsize/wsize.
The only one I confirmed was cxgb3, but it has already been removed
from the kernel.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Clean up: there is no need to keep two copies of the same value.
Also, in subsequent patches, rpcrdma_ep_create() will be called in
the connect worker rather than at set-up time.
Minor fix: Initialize the transport's sendctx to the value based on
the capabilities of the underlying device, not the maximum setting.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
The size of the sendctx queue depends on the value stored in
ia->ri_max_send_sges. This value is determined by querying the
underlying device.
Eventually, rpcrdma_ia_open() and rpcrdma_ep_create() will be called
in the connect worker rather than at transport set-up time. The
underlying device will not have been chosen device set-up time.
The sendctx queue will thus have to be created after the underlying
device has been chosen via address and route resolution; in other
words, in the connect worker.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Clean-up. The max_send_sge value also happens to be stored in
ep->rep_attr. Let's keep just a single copy.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Since v5.4, a device removal occasionally triggered this oops:
Dec 2 17:13:53 manet kernel: BUG: unable to handle page fault for address: 0000000c00000219
Dec 2 17:13:53 manet kernel: #PF: supervisor read access in kernel mode
Dec 2 17:13:53 manet kernel: #PF: error_code(0x0000) - not-present page
Dec 2 17:13:53 manet kernel: PGD 0 P4D 0
Dec 2 17:13:53 manet kernel: Oops: 0000 [#1] SMP
Dec 2 17:13:53 manet kernel: CPU: 2 PID: 468 Comm: kworker/2:1H Tainted: G W 5.4.0-00050-g53717e43af61 #883
Dec 2 17:13:53 manet kernel: Hardware name: Supermicro SYS-6028R-T/X10DRi, BIOS 1.1a 10/16/2015
Dec 2 17:13:53 manet kernel: Workqueue: ib-comp-wq ib_cq_poll_work [ib_core]
Dec 2 17:13:53 manet kernel: RIP: 0010:rpcrdma_wc_receive+0x7c/0xf6 [rpcrdma]
Dec 2 17:13:53 manet kernel: Code: 6d 8b 43 14 89 c1 89 45 78 48 89 4d 40 8b 43 2c 89 45 14 8b 43 20 89 45 18 48 8b 45 20 8b 53 14 48 8b 30 48 8b 40 10 48 8b 38 <48> 8b 87 18 02 00 00 48 85 c0 75 18 48 8b 05 1e 24 c4 e1 48 85 c0
Dec 2 17:13:53 manet kernel: RSP: 0018:ffffc900035dfe00 EFLAGS: 00010246
Dec 2 17:13:53 manet kernel: RAX: ffff888467290000 RBX: ffff88846c638400 RCX: 0000000000000048
Dec 2 17:13:53 manet kernel: RDX: 0000000000000048 RSI: 00000000f942e000 RDI: 0000000c00000001
Dec 2 17:13:53 manet kernel: RBP: ffff888467611b00 R08: ffff888464e4a3c4 R09: 0000000000000000
Dec 2 17:13:53 manet kernel: R10: ffffc900035dfc88 R11: fefefefefefefeff R12: ffff888865af4428
Dec 2 17:13:53 manet kernel: R13: ffff888466023000 R14: ffff88846c63f000 R15: 0000000000000010
Dec 2 17:13:53 manet kernel: FS: 0000000000000000(0000) GS:ffff88846fa80000(0000) knlGS:0000000000000000
Dec 2 17:13:53 manet kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Dec 2 17:13:53 manet kernel: CR2: 0000000c00000219 CR3: 0000000002009002 CR4: 00000000001606e0
Dec 2 17:13:53 manet kernel: Call Trace:
Dec 2 17:13:53 manet kernel: __ib_process_cq+0x5c/0x14e [ib_core]
Dec 2 17:13:53 manet kernel: ib_cq_poll_work+0x26/0x70 [ib_core]
Dec 2 17:13:53 manet kernel: process_one_work+0x19d/0x2cd
Dec 2 17:13:53 manet kernel: ? cancel_delayed_work_sync+0xf/0xf
Dec 2 17:13:53 manet kernel: worker_thread+0x1a6/0x25a
Dec 2 17:13:53 manet kernel: ? cancel_delayed_work_sync+0xf/0xf
Dec 2 17:13:53 manet kernel: kthread+0xf4/0xf9
Dec 2 17:13:53 manet kernel: ? kthread_queue_delayed_work+0x74/0x74
Dec 2 17:13:53 manet kernel: ret_from_fork+0x24/0x30
The proximal cause is that this rpcrdma_rep has a rr_rdmabuf that
is still pointing to the old ib_device, which has been freed. The
only way that is possible is if this rpcrdma_rep was not destroyed
by rpcrdma_ia_remove.
Debugging showed that was indeed the case: this rpcrdma_rep was
still in use by a completing RPC at the time of the device removal,
and thus wasn't on the rep free list. So, it was not found by
rpcrdma_reps_destroy().
The fix is to introduce a list of all rpcrdma_reps so that they all
can be found when a device is removed. That list is used to perform
only regbuf DMA unmapping, replacing that call to
rpcrdma_reps_destroy().
Meanwhile, to prevent corruption of this list, I've moved the
destruction of temp rpcrdma_rep objects to rpcrdma_post_recvs().
rpcrdma_xprt_drain() ensures that post_recvs (and thus rep_destroy) is
not invoked while rpcrdma_reps_unmap is walking rb_all_reps, thus
protecting the rb_all_reps list.
Fixes: b0b227f071 ("xprtrdma: Use an llist to manage free rpcrdma_reps")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
I've found that on occasion, "rmmod <dev>" will hang while if an NFS
is under load.
Ensure that ri_remove_done is initialized only just before the
transport is woken up to force a close. This avoids the completion
possibly getting initialized again while the CM event handler is
waiting for a wake-up.
Fixes: bebd031866 ("xprtrdma: Support unplugging an HCA from under an NFS mount")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Pull nfsd updates from Bruce Fields:
"This is a relatively quiet cycle for nfsd, mainly various bugfixes.
Possibly most interesting is Trond's fixes for some callback races
that were due to my incomplete understanding of rpc client shutdown.
Unfortunately at the last minute I've started noticing a new
intermittent failure to send callbacks. As the logic seems basically
correct, I'm leaving Trond's patches in for now, and hope to find a
fix in the next week so I don't have to revert those patches"
* tag 'nfsd-5.5' of git://linux-nfs.org/~bfields/linux: (24 commits)
nfsd: depend on CRYPTO_MD5 for legacy client tracking
NFSD fixing possible null pointer derefering in copy offload
nfsd: check for EBUSY from vfs_rmdir/vfs_unink.
nfsd: Ensure CLONE persists data and metadata changes to the target file
SUNRPC: Fix backchannel latency metrics
nfsd: restore NFSv3 ACL support
nfsd: v4 support requires CRYPTO_SHA256
nfsd: Fix cld_net->cn_tfm initialization
lockd: remove __KERNEL__ ifdefs
sunrpc: remove __KERNEL__ ifdefs
race in exportfs_decode_fh()
nfsd: Drop LIST_HEAD where the variable it declares is never used.
nfsd: document callback_wq serialization of callback code
nfsd: mark cb path down on unknown errors
nfsd: Fix races between nfsd4_cb_release() and nfsd4_shutdown_callback()
nfsd: minor 4.1 callback cleanup
SUNRPC: Fix svcauth_gss_proxy_init()
SUNRPC: Trace gssproxy upcall results
sunrpc: fix crash when cache_head become valid before update
nfsd: remove private bin2hex implementation
...
I noticed that for callback requests, the reported backlog latency
is always zero, and the rtt value is crazy big. The problem was that
rqst->rq_xtime is never set for backchannel requests.
Fixes: 78215759e2 ("SUNRPC: Make RTT measurement more ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
NFSoRDMA Client Updates for Linux 5.5
New Features:
- New tracepoints for congestion control and Local Invalidate WRs
Bugfixes and Cleanups:
- Eliminate log noise in call_reserveresult
- Fix unstable connections after a reconnect
- Clean up some code duplication
- Close race between waking a sender and posting a receive
- Fix MR list corruption, and clean up MR usage
- Remove unused rpcrdma_sendctx fields
- Try to avoid DMA mapping pages if it is too costly
- Wake pending tasks if connection fails
- Replace some dprintk()s with tracepoints
If there are RDMA back channel requests being processed by the
server threads, then we should hold a reference to the transport
to ensure it doesn't get freed from underneath us.
Reported-by: Neil Brown <neilb@suse.de>
Fixes: 63cae47005 ("xprtrdma: Handle incoming backward direction RPC calls")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Clean up: Use a single trace point to record each connection's
negotiated inline thresholds and the computed maximum byte size
of transport headers.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
For debugging, the op_connect trace point should report the computed
connect delay. We can then ensure that the delay is computed at the
proper times, for example.
As a further clean-up, remove a few low-value "heartbeat" trace
points in the connect path.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Pending tasks are currently never awoken when the connect worker
fails. The reason is that XPRT_CONNECTED is always clear after a
failure return of rpcrdma_ep_connect, thus the
xprt_test_and_clear_connected() check in xprt_rdma_connect_worker()
always fails.
- xprt_rdma_close always clears XPRT_CONNECTED.
- rpcrdma_ep_connect always clears XPRT_CONNECTED.
After reviewing the TCP connect worker, it appears that there's no
need for extra test_and_set paranoia in xprt_rdma_connect_worker.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
On some platforms, DMA mapping part of a page is more costly than
copying bytes. Restore the pull-up code and use that when we
think it's going to be faster. The heuristic for now is to pull-up
when the size of the RPC message body fits in the buffer underlying
the head iovec.
Indeed, not involving the I/O MMU can help the RPC/RDMA transport
scale better for tiny I/Os across more RDMA devices. This is because
interaction with the I/O MMU is eliminated, as is handling a Send
completion, for each of these small I/Os. Without the explicit
unmapping, the NIC no longer needs to do a costly internal TLB shoot
down for buffers that are just a handful of bytes.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Refactor: Replace spaghetti with code that makes it plain what needs
to be done for each rtype. This makes it easier to add features and
optimizations.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Clean up: This field is not needed in the Send completion handler,
so it can be moved to struct rpcrdma_req to reduce the size of
struct rpcrdma_sendctx, and to reduce the amount of memory that
is sloshed between the sending process and the Send completion
process.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
ia->ri_id is replaced during a reconnect. The connect_worker runs
with the transport send lock held to prevent ri_id from being
dereferenced by the send_request path during this process.
Currently, however, there is no guarantee that ia->ri_id is stable
in the MR recycling worker, which operates in the background and is
not serialized with the connect_worker in any way.
But now that Local_Inv completions are being done in process
context, we can handle the recycling operation there instead of
deferring the recycling work to another process. Because the
disconnect path drains all work before allowing tear down to
proceed, it is guaranteed that Local Invalidations complete only
while the ri_id pointer is stable.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
MRs are now allocated on demand so we can safely throw them away on
disconnect. This way an idle transport can disconnect and it won't
pin hardware MR resources.
Two additional changes:
- Now that all MRs are destroyed on disconnect, there's no need to
check during header marshaling if a req has MRs to recycle. Each
req is sent only once per connection, and now rl_registered is
guaranteed to be empty when rpcrdma_marshal_req is invoked.
- Because MRs are now destroyed in a WQ_MEM_RECLAIM context, they
also must be allocated in a WQ_MEM_RECLAIM context. This reduces
the likelihood that device driver memory allocation will trigger
memory reclaim during NFS writeback.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Close some holes introduced by commit 6dc6ec9e04 ("xprtrdma: Cache
free MRs in each rpcrdma_req") that could result in list corruption.
In addition, the result that is tabulated in @count is no longer
used, so @count is removed.
Fixes: 6dc6ec9e04 ("xprtrdma: Cache free MRs in each rpcrdma_req")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
A recent clean up attempted to separate Receive handling and RPC
Reply processing, in the name of clean layering.
Unfortunately, we can't do this because the Receive Queue has to be
refilled _after_ the most recent credit update from the responder
is parsed from the transport header, but _before_ we wake up the
next RPC sender. That is right in the middle of
rpcrdma_reply_handler().
Usually this isn't a problem because current responder
implementations don't vary their credit grant. The one exception is
when a connection is established: the grant goes from one to a much
larger number on the first Receive. The requester MUST post enough
Receives right then so that any outstanding requests can be sent
without risking RNR and connection loss.
Fixes: 6ceea36890 ("xprtrdma: Refactor Receive accounting")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Clean up/code de-duplication.
Nit: RPC_CWNDSHIFT is incorrect as the initial value for xprt->cwnd.
This mistake does not appear to have operational consequences, since
the cwnd value is replaced with a valid value upon the first Receive
completion.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This is because xprt_request_get_cong() is allowing more than one
RPC Call to be transmitted before the first Receive on the new
connection. The first Receive fills the Receive Queue based on the
server's credit grant. Before that Receive, there is only a single
Receive WR posted because the client doesn't know the server's
credit grant.
Solution is to clear rq_cong on all outstanding rpc_rqsts when the
the cwnd is reset. This is because an RPC/RDMA credit is good for
one connection instance only.
Fixes: 75891f502f ("SUNRPC: Support for congestion control ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
When adding frwr_unmap_async way back when, I re-used the existing
trace_xprtrdma_post_send() trace point to record the return code
of ib_post_send.
Unfortunately there are some cases where re-using that trace point
causes a crash. Instead, construct a trace point specific to posting
Local Invalidate WRs that will always be safe to use in that context,
and will act as a trace log eye-catcher for Local Invalidation.
Fixes: 847568942f ("xprtrdma: Remove fr_state")
Fixes: d8099feda4 ("xprtrdma: Reduce context switching due ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Bill Baker <bill.baker@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
