Commit Graph

158 Commits

Author SHA1 Message Date
Chuck Lever 55f5088c22 svc: Report xprt dequeue latency
Record the time between when a rqstp is enqueued on a transport
and when it is dequeued. This includes how long the rqstp waits on
the queue and how long it takes the kernel scheduler to wake a
nfsd thread to service it.

The svc_xprt_dequeue trace point is altered to include the number
of microseconds between xprt_enqueue and xprt_dequeue.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:13 -04:00
Chuck Lever aaba72cd4e sunrpc: Report per-RPC execution stats
Introduce a mechanism to report the server-side execution latency of
each RPC. The goal is to enable user space to filter the trace
record for latency outliers, build histograms, etc.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:12 -04:00
Chuck Lever ece200ddd5 sunrpc: Save remote presentation address in svc_xprt for trace events
TP_printk defines a format string that is passed to user space for
converting raw trace event records to something human-readable.

My user space's printf (Oracle Linux 7), however, does not have a
%pI format specifier. The result is that what is supposed to be an
IP address in the output of "trace-cmd report" is just a string that
says the field couldn't be displayed.

To fix this, adopt the same approach as the client: maintain a pre-
formated presentation address for occasions when %pI is not
available.

The location of the trace_svc_send trace point is adjusted so that
rqst->rq_xprt is not NULL when the trace event is recorded.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:11 -04:00
Chuck Lever 41f306d0c2 sunrpc: Simplify trace_svc_recv
There doesn't seem to be a lot of value in calling trace_svc_recv
in the failing case.

1. There are two very common cases: one is the transport is not
ready, and the other is shutdown. Neither is terribly interesting.

2. The trace record for the failing case contains nothing but
the status code.

Therefore the trace point call site in the error exit is removed.
Since the trace point is now recording a length instead of a
status, rename the status field and remove the case that records a
zero XID.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:11 -04:00
Chuck Lever 7dbb53baed sunrpc: Simplify do_enqueue tracing
There are three cases where svc_xprt_do_enqueue() returns without
waking an nfsd thread:

1. There is no work to do

2. The transport is already busy

3. There are no available nfsd threads

Only 3. is truly interesting. Move the trace point so it records
that there was work to do and either an nfsd thread was awoken, or
a free one could not found.

As an additional clean up, remove a redundant comment and a couple
of dprintk call sites.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:11 -04:00
Chuck Lever caa3e106dc sunrpc: Move trace_svc_xprt_dequeue()
Reduce the amount of noise generated by trace_svc_xprt_dequeue by
moving it to the end of svc_get_next_xprt. This generates exactly
one trace event when a ready xprt is found, rather than spurious
events when there is no work to do. The empty events contain no
information that can't be obtained simply by tracing function calls
to svc_xprt_dequeue.

A small additional benefit is simplification of the svc_xprt_event
trace class, which no longer has to handle the case when the @xprt
parameter is NULL.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:10 -04:00
Chuck Lever 989f881ebf svc: Simplify ->xpo_secure_port
Clean up: Instead of returning a value that is used to set or clear
a bit, just make ->xpo_secure_port mangle that bit, and return void.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:09 -04:00
Chuck Lever 63a1b15693 sunrpc: Remove unneeded pointer dereference
Clean up: Noticed during code inspection that there is already a
local automatic variable "xprt" so dereferencing rqst->rq_xprt
again is unnecessary.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2018-04-03 15:08:09 -04:00
Kees Cook 841b86f328 treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts
With all callbacks converted, and the timer callback prototype
switched over, the TIMER_FUNC_TYPE cast is no longer needed,
so remove it. Conversion was done with the following scripts:

    perl -pi -e 's|\(TIMER_FUNC_TYPE\)||g' \
        $(git grep TIMER_FUNC_TYPE | cut -d: -f1 | sort -u)

    perl -pi -e 's|\(TIMER_DATA_TYPE\)||g' \
        $(git grep TIMER_DATA_TYPE | cut -d: -f1 | sort -u)

The now unused macros are also dropped from include/linux/timer.h.

Signed-off-by: Kees Cook <keescook@chromium.org>
2017-11-21 16:35:54 -08:00
Linus Torvalds 4dd3c2e5a4 Lots of good bugfixes, including:
- fix a number of races in the NFSv4+ state code.
 	- fix some shutdown crashes in multiple-network-namespace cases.
 	- relax our 4.1 session limits; if you've an artificially low limit
 	  to the number of 4.1 clients that can mount simultaneously, try
 	  upgrading.
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Merge tag 'nfsd-4.15' of git://linux-nfs.org/~bfields/linux

Pull nfsd updates from Bruce Fields:
 "Lots of good bugfixes, including:

   -  fix a number of races in the NFSv4+ state code

   -  fix some shutdown crashes in multiple-network-namespace cases

   -  relax our 4.1 session limits; if you've an artificially low limit
      to the number of 4.1 clients that can mount simultaneously, try
      upgrading"

* tag 'nfsd-4.15' of git://linux-nfs.org/~bfields/linux: (22 commits)
  SUNRPC: Improve ordering of transport processing
  nfsd: deal with revoked delegations appropriately
  svcrdma: Enqueue after setting XPT_CLOSE in completion handlers
  nfsd: use nfs->ns.inum as net ID
  rpc: remove some BUG()s
  svcrdma: Preserve CB send buffer across retransmits
  nfds: avoid gettimeofday for nfssvc_boot time
  fs, nfsd: convert nfs4_file.fi_ref from atomic_t to refcount_t
  fs, nfsd: convert nfs4_cntl_odstate.co_odcount from atomic_t to refcount_t
  fs, nfsd: convert nfs4_stid.sc_count from atomic_t to refcount_t
  lockd: double unregister of inetaddr notifiers
  nfsd4: catch some false session retries
  nfsd4: fix cached replies to solo SEQUENCE compounds
  sunrcp: make function _svc_create_xprt static
  SUNRPC: Fix tracepoint storage issues with svc_recv and svc_rqst_status
  nfsd: use ARRAY_SIZE
  nfsd: give out fewer session slots as limit approaches
  nfsd: increase DRC cache limit
  nfsd: remove unnecessary nofilehandle checks
  nfs_common: convert int to bool
  ...
2017-11-18 11:22:04 -08:00
Trond Myklebust 22700f3c6d SUNRPC: Improve ordering of transport processing
Since it can take a while before a specific thread gets scheduled, it
is better to just implement a first come first served queue mechanism.
That way, if a thread is already scheduled and is idle, it can pick up
the work to do from the queue.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2017-11-07 16:44:03 -05:00
Colin Ian King da36e6dbf4 sunrcp: make function _svc_create_xprt static
The function _svc_create_xprt is local to the source and
does not need to be in global scope, so make it static.

Cleans up sparse warning:
symbol '_svc_create_xprt' was not declared. Should it be static?

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2017-11-07 16:43:57 -05:00
Kees Cook ff861c4d64 sunrpc: Convert timers to use timer_setup()
In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@poochiereds.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-18 12:40:27 +01:00
Chuck Lever 8c6ae4980e sunrpc: Allocate up to RPCSVC_MAXPAGES per svc_rqst
svcrdma needs 259 pages allocated to receive 1MB NFSv4.0 WRITE requests:

 - 1 page for the transport header and head iovec
 - 256 pages for the data payload
 - 1 page for the trailing GETATTR request (since NFSD XDR decoding
   does not look for a tail iovec, the GETATTR is stuck at the end
   of the rqstp->rq_arg.pages list)
 - 1 page for building the reply xdr_buf

But RPCSVC_MAXPAGES is already 259 (on x86_64). The problem is that
svc_alloc_arg never allocates that many pages. To address this:

1. The final element of rq_pages always points to NULL. To
   accommodate up to 259 pages in rq_pages, add an extra element
   to rq_pages for the array termination sentinel.

2. Adjust the calculation of "pages" to match how RPCSVC_MAXPAGES
   is calculated, so it can go up to 259. Bruce noted that the
   calculation assumes sv_max_mesg is a multiple of PAGE_SIZE,
   which might not always be true. I didn't change this assumption.

3. Change the loop boundaries to allow 259 pages to be allocated.

Additional clean-up: WARN_ON_ONCE adds an extra conditional branch,
which is basically never taken. And there's no need to dump the
stack here because svc_alloc_arg has only one caller.

Keeping that NULL "array termination sentinel"; there doesn't appear to
be any code that depends on it, only code in nfsd_splice_actor() which
needs the 259th element to be initialized to *something*.  So it's
possible we could just keep the array at 259 elements and drop that
final NULL, but we're being conservative for now.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2017-07-12 15:54:55 -04:00
Linus Torvalds 42e1b14b6e Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Implement wraparound-safe refcount_t and kref_t types based on
     generic atomic primitives (Peter Zijlstra)

   - Improve and fix the ww_mutex code (Nicolai Hähnle)

   - Add self-tests to the ww_mutex code (Chris Wilson)

   - Optimize percpu-rwsems with the 'rcuwait' mechanism (Davidlohr
     Bueso)

   - Micro-optimize the current-task logic all around the core kernel
     (Davidlohr Bueso)

   - Tidy up after recent optimizations: remove stale code and APIs,
     clean up the code (Waiman Long)

   - ... plus misc fixes, updates and cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
  fork: Fix task_struct alignment
  locking/spinlock/debug: Remove spinlock lockup detection code
  lockdep: Fix incorrect condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS
  lkdtm: Convert to refcount_t testing
  kref: Implement 'struct kref' using refcount_t
  refcount_t: Introduce a special purpose refcount type
  sched/wake_q: Clarify queue reinit comment
  sched/wait, rcuwait: Fix typo in comment
  locking/mutex: Fix lockdep_assert_held() fail
  locking/rtmutex: Flip unlikely() branch to likely() in __rt_mutex_slowlock()
  locking/rwsem: Reinit wake_q after use
  locking/rwsem: Remove unnecessary atomic_long_t casts
  jump_labels: Move header guard #endif down where it belongs
  locking/atomic, kref: Implement kref_put_lock()
  locking/ww_mutex: Turn off __must_check for now
  locking/atomic, kref: Avoid more abuse
  locking/atomic, kref: Use kref_get_unless_zero() more
  locking/atomic, kref: Kill kref_sub()
  locking/atomic, kref: Add kref_read()
  locking/atomic, kref: Add KREF_INIT()
  ...
2017-02-20 13:23:30 -08:00
Peter Zijlstra 2c935bc572 locking/atomic, kref: Add kref_read()
Since we need to change the implementation, stop exposing internals.

Provide kref_read() to read the current reference count; typically
used for debug messages.

Kills two anti-patterns:

	atomic_read(&kref->refcount)
	kref->refcount.counter

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-14 11:37:18 +01:00
Scott Mayhew 546125d161 sunrpc: don't call sleeping functions from the notifier block callbacks
The inet6addr_chain is an atomic notifier chain, so we can't call
anything that might sleep (like lock_sock)... instead of closing the
socket from svc_age_temp_xprts_now (which is called by the notifier
function), just have the rpc service threads do it instead.

Cc: stable@vger.kernel.org
Fixes: c3d4879e01 "sunrpc: Add a function to close..."
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2017-01-12 15:56:40 -05:00
Scott Mayhew ea08e39230 sunrpc: svc_age_temp_xprts_now should not call setsockopt non-tcp transports
This fixes the following panic that can occur with NFSoRDMA.

general protection fault: 0000 [#1] SMP
Modules linked in: rpcrdma ib_isert iscsi_target_mod ib_iser libiscsi
scsi_transport_iscsi ib_srpt target_core_mod ib_srp scsi_transport_srp
scsi_tgt ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm
mlx5_ib ib_core intel_powerclamp coretemp kvm_intel kvm sg ioatdma
ipmi_devintf ipmi_ssif dcdbas iTCO_wdt iTCO_vendor_support pcspkr
irqbypass sb_edac shpchp dca crc32_pclmul ghash_clmulni_intel edac_core
lpc_ich aesni_intel lrw gf128mul glue_helper ablk_helper mei_me mei
ipmi_si cryptd wmi ipmi_msghandler acpi_pad acpi_power_meter nfsd
auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sd_mod
crc_t10dif crct10dif_generic mgag200 i2c_algo_bit drm_kms_helper
syscopyarea sysfillrect sysimgblt ahci fb_sys_fops ttm libahci mlx5_core
tg3 crct10dif_pclmul drm crct10dif_common
ptp i2c_core libata crc32c_intel pps_core fjes dm_mirror dm_region_hash
dm_log dm_mod
CPU: 1 PID: 120 Comm: kworker/1:1 Not tainted 3.10.0-514.el7.x86_64 #1
Hardware name: Dell Inc. PowerEdge R320/0KM5PX, BIOS 2.4.2 01/29/2015
Workqueue: events check_lifetime
task: ffff88031f506dd0 ti: ffff88031f584000 task.ti: ffff88031f584000
RIP: 0010:[<ffffffff8168d847>]  [<ffffffff8168d847>]
_raw_spin_lock_bh+0x17/0x50
RSP: 0018:ffff88031f587ba8  EFLAGS: 00010206
RAX: 0000000000020000 RBX: 20041fac02080072 RCX: ffff88031f587fd8
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 20041fac02080072
RBP: ffff88031f587bb0 R08: 0000000000000008 R09: ffffffff8155be77
R10: ffff880322a59b00 R11: ffffea000bf39f00 R12: 20041fac02080072
R13: 000000000000000d R14: ffff8800c4fbd800 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff880322a40000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3c52d4547e CR3: 00000000019ba000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
20041fac02080002 ffff88031f587bd0 ffffffff81557830 20041fac02080002
ffff88031f587c78 ffff88031f587c40 ffffffff8155ae08 000000010157df32
0000000800000001 ffff88031f587c20 ffffffff81096acb ffffffff81aa37d0
Call Trace:
[<ffffffff81557830>] lock_sock_nested+0x20/0x50
[<ffffffff8155ae08>] sock_setsockopt+0x78/0x940
[<ffffffff81096acb>] ? lock_timer_base.isra.33+0x2b/0x50
[<ffffffff8155397d>] kernel_setsockopt+0x4d/0x50
[<ffffffffa0386284>] svc_age_temp_xprts_now+0x174/0x1e0 [sunrpc]
[<ffffffffa03b681d>] nfsd_inetaddr_event+0x9d/0xd0 [nfsd]
[<ffffffff81691ebc>] notifier_call_chain+0x4c/0x70
[<ffffffff810b687d>] __blocking_notifier_call_chain+0x4d/0x70
[<ffffffff810b68b6>] blocking_notifier_call_chain+0x16/0x20
[<ffffffff815e8538>] __inet_del_ifa+0x168/0x2d0
[<ffffffff815e8cef>] check_lifetime+0x25f/0x270
[<ffffffff810a7f3b>] process_one_work+0x17b/0x470
[<ffffffff810a8d76>] worker_thread+0x126/0x410
[<ffffffff810a8c50>] ? rescuer_thread+0x460/0x460
[<ffffffff810b052f>] kthread+0xcf/0xe0
[<ffffffff810b0460>] ? kthread_create_on_node+0x140/0x140
[<ffffffff81696418>] ret_from_fork+0x58/0x90
[<ffffffff810b0460>] ? kthread_create_on_node+0x140/0x140
Code: ca 75 f1 5d c3 0f 1f 80 00 00 00 00 eb d9 66 0f 1f 44 00 00 0f 1f
44 00 00 55 48 89 e5 53 48 89 fb e8 7e 04 a0 ff b8 00 00 02 00 <f0> 0f
c1 03 89 c2 c1 ea 10 66 39 c2 75 03 5b 5d c3 83 e2 fe 0f
RIP  [<ffffffff8168d847>] _raw_spin_lock_bh+0x17/0x50
RSP <ffff88031f587ba8>

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fixes: c3d4879e ("sunrpc: Add a function to close temporary transports immediately")
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2016-11-14 10:30:58 -05:00
Trond Myklebust f4a4906e56 SUNRPC: Remove unused callback xpo_adjust_wspace()
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2016-07-13 15:53:50 -04:00
Trond Myklebust ff3ac5c3dc SUNRPC: Add a server side per-connection limit
Allow the user to limit the number of requests serviced through a single
connection, to help prevent faster clients from starving slower clients.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2016-07-13 15:53:48 -04:00
Trond Myklebust 104f6351f7 SUNRPC: Add tracepoints for dropped and deferred requests
Dropping and/or deferring requests has an impact on performance. Let's
make sure we can trace those events.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2016-07-13 15:53:43 -04:00
Trond Myklebust 82ea2d7615 SUNRPC: Add a tracepoint for server socket out-of-space conditions
Add a tracepoint to track when the processing of incoming RPC data gets
deferred due to out-of-space issues on the outgoing transport.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2016-07-13 15:53:42 -04:00
J. Bruce Fields 39a9beab5a rpc: share one xps between all backchannels
The spec allows backchannels for multiple clients to share the same tcp
connection.  When that happens, we need to use the same xprt for all of
them.  Similarly, we need the same xps.

This fixes list corruption introduced by the multipath code.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>
2016-06-15 10:32:25 -04:00
J. Bruce Fields d96b9c9398 svcrpc: autoload rdma module
This should fix failures like:

	# rpc.nfsd --rdma
	rpc.nfsd: Unable to request RDMA services: Protocol not supported

Reported-by: Steve Dickson <steved@redhat.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2016-05-23 10:55:24 -04:00
Scott Mayhew c3d4879e01 sunrpc: Add a function to close temporary transports immediately
Add a function svc_age_temp_xprts_now() to close temporary transports
whose xpt_local matches the address passed in server_addr immediately
instead of waiting for them to be closed by the timer function.

The function is intended to be used by notifier_blocks that will be
added to nfsd and lockd that will run when an ip address is deleted.

This will eliminate the ACK storms and client hangs that occur in
HA-NFS configurations where nfsd & lockd is left running on the cluster
nodes all the time and the NFS 'service' is migrated back and forth
within a short timeframe.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-12-23 10:08:15 -05:00
Jeff Layton b9e13cdfac nfsd/sunrpc: turn enqueueing a svc_xprt into a svc_serv operation
For now, all services use svc_xprt_do_enqueue, but once we add
workqueue-based service support, we'll need to do something different.

Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Tested-by: Shirley Ma <shirley.ma@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-08-10 16:05:42 -04:00
Jeff Layton 3c5199143b sunrpc/lockd: fix references to the BKL
The BKL is completely out of the picture in the lockd and sunrpc code
these days. Update the antiquated comments that refer to it.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2015-01-23 10:29:12 -05:00
Jeff Layton acf06a7fa1 sunrpc: only call test_bit once in svc_xprt_received
...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>
2014-12-09 11:29:14 -05:00
Jeff Layton 83a712e0af sunrpc: add some tracepoints around enqueue and dequeue of svc_xprt
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>
2014-12-09 11:29:14 -05:00
Jeff Layton b1691bc03d sunrpc: convert to lockless lookup of queued server threads
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>
2014-12-09 11:22:22 -05:00
Jeff Layton 403c7b4444 sunrpc: fix potential races in pool_stats collection
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>
2014-12-09 11:22:22 -05:00
Jeff Layton ceff739c53 sunrpc: have svc_wake_up only deal with pool 0
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>
2014-12-09 11:22:21 -05:00
Jeff Layton 4d5db3f536 sunrpc: convert sp_task_pending flag to use atomic bitops
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>
2014-12-09 11:22:21 -05:00
Jeff Layton 78b65eb3fd sunrpc: move rq_dropme flag into rq_flags
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09 11:22:20 -05:00
Jeff Layton 30660e04b0 sunrpc: move rq_usedeferral flag to rq_flags
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-12-09 11:22:20 -05:00
Jeff Layton 4d152e2c9a sunrpc: add a generic rq_flags field to svc_rqst and move rq_secure to it
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>
2014-12-09 11:21:20 -05:00
J. Bruce Fields 2941b0e91b NFS client updates for Linux 3.19
Highlights include:
 
 Features:
 - NFSv4.2 client support for hole punching and preallocation.
 - Further RPC/RDMA client improvements.
 - Add more RPC transport debugging tracepoints.
 - Add RPC debugging tools in debugfs.
 
 Bugfixes:
 - Stable fix for layoutget error handling
 - Fix a change in COMMIT behaviour resulting from the recent io code updates
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Merge tag 'nfs-for-3.19-1' into nfsd for-3.19 branch

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.
2014-12-09 11:12:26 -05:00
Jeff Layton 8d65ef760d sunrpc: eliminate the XPT_DETACHED flag
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>
2014-12-01 12:45:26 -07:00
Jeff Layton 860a0d9e51 sunrpc: add some tracepoints in svc_rqst handling functions
...just around svc_send, svc_recv and svc_process for now.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2014-11-24 12:53:34 -05:00
J. Bruce Fields ae89254da6 SUNRPC: Fix compile on non-x86
current_task appears to be x86-only, oops.

Let's just delete this check entirely:

Any developer that adds a new user without setting rq_task will get a
crash the first time they test it.  I also don't think there are
normally any important locks held here, and I can't see any other reason
why killing a server thread would bring the whole box down.

So the effort to fail gracefully here looks like overkill.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 983c684466 "SUNRPC: get rid of the request wait queue"
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-08-28 15:51:35 -04:00
Trond Myklebust 0c0746d03e SUNRPC: More optimisations of svc_xprt_enqueue()
Just move the transport locking out of the spin lock protected area
altogether.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-08-17 12:00:11 -04:00
Trond Myklebust a4aa8054a6 SUNRPC: Fix broken kthread_should_stop test in svc_get_next_xprt
We should definitely not be exiting svc_get_next_xprt() with the
thread enqueued. Fix this by ensuring that we fall through to
the dequeue.
Also move the test itself outside the spin lock protected section.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-08-17 12:00:11 -04:00
Trond Myklebust 983c684466 SUNRPC: get rid of the request wait queue
We're always _only_ waking up tasks from within the sp_threads list, so
we know that they are enqueued and alive. The rq_wait waitqueue is just
a distraction with extra atomic semantics.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-08-17 12:00:11 -04:00
Trond Myklebust 106f359cf4 SUNRPC: Do not grab pool->sp_lock unnecessarily in svc_get_next_xprt
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-08-17 12:00:10 -04:00
Trond Myklebust 9e5b208dc9 SUNRPC: Do not override wspace tests in svc_handle_xprt
We already determined that there was enough wspace when we
called svc_xprt_enqueue.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-08-17 12:00:10 -04:00
Trond Myklebust 518776800c SUNRPC: Allow svc_reserve() to notify TCP socket that space has been freed
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-29 16:10:20 -04:00
Trond Myklebust 0971374e28 SUNRPC: Reduce contention in svc_xprt_enqueue()
Ensure that all calls to svc_xprt_enqueue() except svc_xprt_received()
check the value of XPT_BUSY, before attempting to grab spinlocks etc.
This is to avoid situations such as the following "perf" trace,
which shows heavy contention on the pool spinlock:

    54.15%            nfsd  [kernel.kallsyms]        [k] _raw_spin_lock_bh
                      |
                      --- _raw_spin_lock_bh
                         |
                         |--71.43%-- svc_xprt_enqueue
                         |          |
                         |          |--50.31%-- svc_reserve
                         |          |
                         |          |--31.35%-- svc_xprt_received
                         |          |
                         |          |--18.34%-- svc_tcp_data_ready
...

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-07-29 16:10:15 -04:00
J. Bruce Fields 2825a7f907 nfsd4: allow encoding across page boundaries
After this we can handle for example getattr of very large ACLs.

Read, readdir, readlink are still special cases with their own limits.

Also we can't handle a new operation starting close to the end of a
page.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-05-30 17:31:54 -04:00
Trond Myklebust c789102c20 SUNRPC: Fix a module reference leak in svc_handle_xprt
If the accept() call fails, we need to put the module reference.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-05-22 15:57:22 -04:00
Chuck Lever 16e4d93f6d NFSD: Ignore client's source port on RDMA transports
An NFS/RDMA client's source port is meaningless for RDMA transports.
The transport layer typically sets the source port value on the
connection to a random ephemeral port.

Currently, NFS server administrators must specify the "insecure"
export option to enable clients to access exports via RDMA.

But this means NFS clients can access such an export via IP using an
ephemeral port, which may not be desirable.

This patch eliminates the need to specify the "insecure" export
option to allow NFS/RDMA clients access to an export.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=250
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2014-05-22 15:55:48 -04:00