Commit Graph

210184 Commits

Author SHA1 Message Date
Andy Grover
ce47f52f42 RDS: Update comments in rds_send_xmit()
Update comments to reflect changes in previous commit.

Keeping as separate commits due to different authorship.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:25 -07:00
Chris Mason
9e29db0e36 RDS: Use a generation counter to avoid rds_send_xmit loop
rds_send_xmit is required to loop around after it releases the lock
because someone else could done a trylock, found someone working on the
list and backed off.

But, once we drop our lock, it is possible that someone else does come
in and make progress on the list.  We should detect this and not loop
around if another process is actually working on the list.

This patch adds a generation counter that is bumped every time we
get the lock and do some send work.  If the retry notices someone else
has bumped the generation counter, it does not need to loop around and
continue working.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:24 -07:00
Andy Grover
acfcd4d4ec RDS: Get pong working again
Call send_xmit() directly from pong()

Set pongs as op_active

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:23 -07:00
Andy Grover
a40aa9233a RDS: Do wait_event_interruptible instead of wait_event
Can't see a reason not to allow signals to interrupt the wait.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:22 -07:00
Andy Grover
fcc5450c63 RDS: Remove send_quota from send_xmit()
The purpose of the send quota was really to give fairness
when different connections were all using the same
workq thread to send backlogged msgs -- they could only send
so many before another connection could make progress.

Now that each connection is pushing the backlog from its
completion handler, they are all guaranteed to make progress
and the quota isn't needed any longer.

A thread *will* have to send all previously queued data, as well
as any further msgs placed on the queue while while c_send_lock
was held. In a pathological case a single process can get
roped into doing this for long periods while other threads
get off free. But, since it can only do this until the transport
reports full, this is a bounded scenario.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:21 -07:00
Andy Grover
51e2cba8b5 RDS: Move atomic stats from general to ib-specific area
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:20 -07:00
Andy Grover
ab1a6926f5 RDS: rds_message_unmapped() doesn't need to check if queue active
If the queue has nobody on it, then wake_up does nothing.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:19 -07:00
Andy Grover
cf4b7389ee RDS: Fix locking in send on m_rs_lock
Do not nest m_rs_lock under c_lock

Disable interrupts in {rdma,atomic}_send_complete

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:18 -07:00
Andy Grover
f2ec76f288 RDS: Use NOWAIT in message_map_pages()
Can no longer block, so use NOWAIT.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:17 -07:00
Andy Grover
2fa57129df RDS: Bypass workqueue when queueing cong updates
Now that rds_send_xmit() does not block, we can call it directly
instead of going through the helper thread.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:16 -07:00
Andy Grover
a7d3a28148 RDS: Call rds_send_xmit() directly from sendmsg()
rds_sendmsg() is calling the send worker function to
send the just-queued datagrams, presumably because it wants
the behavior where anything not sent will re-call the send
worker. We now ensure all queued datagrams are sent by retrying
from the send completion handler, so this isn't needed any more.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:15 -07:00
Andy Grover
2ad8099b58 RDS: rds_send_xmit() locking/irq fixes
rds_message_put() cannot be called with irqs off, so move it after
irqs are re-enabled.

Spinlocks throughout the function do not to use _irqsave because
the lock of c_send_lock at top already disabled irqs.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:13 -07:00
Andy Grover
049ee3f500 RDS: Change send lock from a mutex to a spinlock
This change allows us to call rds_send_xmit() from a tasklet,
which is crucial to our new operating model.

* Change c_send_lock to a spinlock
* Update stats fields "sem_" to "_lock"
* Remove unneeded rds_conn_is_sending()

About locking between shutdown and send -- send checks if the
connection is up. Shutdown puts the connection into
DISCONNECTING. After this, all threads entering send will exit
immediately. However, a thread could be *in* send_xmit(), so
shutdown acquires the c_send_lock to ensure everyone is out
before proceeding with connection shutdown.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:12 -07:00
Andy Grover
f17a1a55fb RDS: Refill recv ring directly from tasklet
Performance is better if we use allocations that don't block
to refill the receive ring. Since the whole reason we were
kicking out to the worker thread was so we could do blocking
allocs, we no longer need to do this.

Remove gfp params from rds_ib_recv_refill(); we always use
GFP_NOWAIT.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:11 -07:00
Andy Grover
77dd550e55 RDS: Stop supporting old cong map sending method
We now ask the transport to give us a rm for the congestion
map, and then we handle it normally. Previously, the
transport defined a function that we would call to send
a congestion map.

Convert TCP and loop transports to new cong map method.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:10 -07:00
Andy Grover
e32b4a7049 RDS/IB: Do not wait for send ring to be empty on conn shutdown
Now that we are signaling send completions much less, we are likely
to have dirty entries in the send queue when the connection is
shut down (on rmmod, for example.) These are cleaned up a little
further down in conn_shutdown, but if we wait on the ring_empty_wait
for them, it'll never happen, and we hand on unload.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:09 -07:00
Andy Grover
ff3d7d3613 RDS: Perform unmapping ops in stages
Previously, RDS would wait until the final send WR had completed
and then handle cleanup. With silent ops, we do not know
if an atomic, rdma, or data op will be last. This patch
handles any of these cases by keeping a pointer to the last
op in the message in m_last_op.

When the TX completion event fires, rds dispatches to per-op-type
cleanup functions, and then does whole-message cleanup, if the
last op equalled m_last_op.

This patch also moves towards having op-specific functions take
the op struct, instead of the overall rm struct.

rds_ib_connection has a pointer to keep track of a a partially-
completed data send operation. This patch changes it from an
rds_message pointer to the narrower rm_data_op pointer, and
modifies places that use this pointer as needed.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:08 -07:00
Andy Grover
aa0a4ef4ac RDS: Make sure cmsgs aren't used in improper ways
It hasn't cropped up in the field, but this code ensures it is
impossible to issue operations that pass an rdma cookie (DEST, MAP)
in the same sendmsg call that's actually initiating rdma or atomic
ops.

Disallowing this perverse-but-technically-allowed usage makes silent
RDMA heuristics slightly easier.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:07 -07:00
Andy Grover
2c3a5f9abb RDS: Add flag for silent ops. Do atomic op before RDMA
Add a flag to the API so users can indicate they want
silent operations. This is needed because silent ops
cannot be used with USE_ONCE MRs, so we can't just
assume silent.

Also, change send_xmit to do atomic op before rdma op if
both are present, and centralize the hairy logic to determine if
we want to attempt silent, or not.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:06 -07:00
Andy Grover
7e3bd65ebf RDS: Move some variables around for consistency
Also, add a comment.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:05 -07:00
Andy Grover
940786eb0a RDS: queue failure notifications for dropped atomic ops
When dropping ops in the send queue, we notify the client
of failed rdma ops they asked for notifications on, but not
atomic ops. It should be for both.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:04 -07:00
Andy Grover
ee4c7b47e4 RDS: Add a warning if trying to allocate 0 sgs
rds_message_alloc_sgs() only works when nents is nonzero.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:03 -07:00
Andy Grover
372cd7dedf RDS: Do not set op_active in r_m_copy_from_user().
Do not allocate sgs for data for 0-length datagrams

Set data.op_active in rds_sendmsg() instead of
rds_message_copy_from_user().

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:02 -07:00
Andy Grover
5b2366bd28 RDS: Rewrite rds_send_xmit
Simplify rds_send_xmit().

Send a congestion map (via xmit_cong_map) without
decrementing send_quota.

Move resetting of conn xmit variables to end of loop.

Update comments.

Implement a special case to turn off sending an rds header
when there is an atomic op and no other data.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:12:01 -07:00
Andy Grover
6c7cc6e469 RDS: Rename data op members prefix from m_ to op_
For consistency.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:59 -07:00
Andy Grover
f8b3aaf2ba RDS: Remove struct rds_rdma_op
A big changeset, but it's all pretty dumb.

struct rds_rdma_op was already embedded in struct rm_rdma_op.
Remove rds_rdma_op and put its members in rm_rdma_op. Rename
members with "op_" prefix instead of "r_", for consistency.

Of course this breaks a lot, so fixup the code accordingly.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:58 -07:00
Andy Grover
d0ab25a83c RDS: purge atomic resources too in rds_message_purge()
Add atomic_free_op function, analogous to rdma_free_op,
and call it in rds_message_purge().

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:57 -07:00
Andy Grover
4324879df0 RDS: Inline rdma_prepare into cmsg_rdma_args
cmsg_rdma_args just calls rdma_prepare and does a little
arg checking -- not quite enough to justify its existence.
Plus, it is the only caller of rdma_prepare().

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:56 -07:00
Andy Grover
241eef3e2f RDS: Implement silent atomics
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:55 -07:00
Andy Grover
d37c935905 RDS: Move loop-only function to loop.c
Also, try to better-document the locking around the
rm and its m_inc in loop.c.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:54 -07:00
Andy Grover
c8de3f1005 RDS/IB: Make all flow control code conditional on i_flowctl
Maybe things worked fine with the flow control code running
even in the non-flow-control case, but making it explicitly
conditional helps the non-fc case be easier to read.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:53 -07:00
Andy Grover
1d34f17571 RDS: Remove unsignaled_bytes sysctl
Removed unsignaled_bytes sysctl and code to signal
based on it. I believe unsignaled_wrs is more than
sufficient for our purposes.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:52 -07:00
Andy Grover
da5a06cef5 RDS: rewrite rds_ib_xmit
Now that the header always goes first, it is possible to
simplify rds_ib_xmit. Instead of having a path to handle 0-byte
dgrams and another path to handle >0, these can both be handled
in one path. This lets us eliminate xmit_populate_wr().

Rename sent to bytes_sent, to differentiate better from other
variable named "send".

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:51 -07:00
Andy Grover
919ced4ce7 RDS/IB: Remove ib_[header/data]_sge() functions
These functions were to cope with differently ordered
sg entries depending on RDS 3.0 or 3.1+. Now that
we've dropped 3.0 compatibility we no longer need them.

Also, modify usage sites for these to refer to sge[0] or [1]
directly. Reorder code to initialize header sgs first.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:50 -07:00
Andy Grover
6f3d05db0d RDS/IB: Remove dead code
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:49 -07:00
Andy Grover
f147dd9eca RDS/IB: Disallow connections less than RDS 3.1
RDS 3.0 connections (in OFED 1.3 and earlier) put the
header at the end. 3.1 connections put it at the head.
The code has significant added complexity in order to
handle both configurations. In OFED 1.6 we can
drop this and simplify the code by only supporting
"header-first" configuration.

This patch checks the protocol version, and if prior
to 3.1, does not complete the connection.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:48 -07:00
Andy Grover
9c030391e8 RDS/IB: eliminate duplicate code
both atomics and rdmas need to convert ib-specific completion codes
into RDS status codes. Rename rds_ib_rdma_send_complete to
rds_ib_send_complete, and have it take a pointer to the function to
call with the new error code.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:47 -07:00
Andy Grover
809fa148a2 RDS: inc_purge() transport function unused - remove it
Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:46 -07:00
Andy Grover
6200ed7799 RDS: Whitespace
Tidy up some whitespace issues.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:44 -07:00
Andy Grover
d22faec22c RDS: Do not mask address when pinning pages
This does not appear to be necessary.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:43 -07:00
Andy Grover
40589e74f7 RDS: Base init_depth and responder_resources on hw values
Instead of using a constant for initiator_depth and
responder_resources, read the per-QP values when the
device is enumerated, and then use these values when creating
the connection.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:42 -07:00
Andy Grover
15133f6e67 RDS: Implement atomic operations
Implement a CMSG-based interface to do FADD and CSWP ops.

Alter send routines to handle atomic ops.

Add atomic counters to stats.

Add xmit_atomic() to struct rds_transport

Inline rds_ib_send_unmap_rdma into unmap_rm

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:41 -07:00
Andy Grover
a63273d499 RDS: Clear up some confusing code in send_remove_from_sock
The previous code was correct, but made the assumption that
if r_notifier was non-NULL then either r_recverr or r_notify
was true. Valid, but fragile. Changed to explicitly check
r_recverr (shows up in greps for recverr now, too.)

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:40 -07:00
Andy Grover
f4dd96f7b2 RDS: make sure all sgs alloced are initialized
rds_message_alloc_sgs() now returns correctly-initialized
sg lists, so calleds need not do this themselves.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:39 -07:00
Andy Grover
ff87e97a9d RDS: make m_rdma_op a member of rds_message
This eliminates a separate memory alloc, although
it is now necessary to add an "r_active" flag, since
it is no longer to use the m_rdma_op pointer as an
indicator of if an rdma op is present.

rdma SGs allocated from rm sg pool.

rds_rm_size also gets bigger. It's a little inefficient to
run through CMSGs twice, but it makes later steps a lot smoother.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:38 -07:00
Andy Grover
21f79afa5f RDS: fold rdma.h into rds.h
RDMA is now an intrinsic part of RDS, so it's easier to just have
a single header.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:37 -07:00
Andy Grover
fc445084f1 RDS: Explicitly allocate rm in sendmsg()
r_m_copy_from_user used to allocate the rm as well as kernel
buffers for the data, and then copy the data in. Now, sendmsg()
allocates the rm, although the data buffer alloc still happens
in r_m_copy_from_user.

SGs are still allocated with rm, but now r_m_alloc_sgs() is
used to reserve them. This allows multiple SG lists to be
allocated from the one rm -- this is important once we also
want to alloc our rdma sgl from this pool.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:36 -07:00
Andy Grover
3ef13f3c22 RDS: cleanup/fix rds_rdma_unuse
First, it looks to me like the atomic_inc is wrong.
We should be decrementing refcount only once here, no? It's
already being done by the mr_put() at the end.

Second, simplify the logic a bit by bailing early (with a warning)
if !mr.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:35 -07:00
Andy Grover
e779137aa7 RDS: break out rdma and data ops into nested structs in rds_message
Clearly separate rdma-related variables in rm from data-related ones.
This is in anticipation of adding atomic support.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:33 -07:00
Andy Grover
8690bfa17a RDS: cleanup: remove "== NULL"s and "!= NULL"s in ptr comparisons
Favor "if (foo)" style over "if (foo != NULL)".

Signed-off-by: Andy Grover <andy.grover@oracle.com>
2010-09-08 18:11:32 -07:00