Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 174 insertions, 0 deletions

diff --git a/Documentation/networking/multi-pf-netdev.rst b/Documentation/networking/multi-pf-netdev.rst
new file mode 100644
index 000000000..2f5a5bb3c
--- /dev/null
+++ b/Documentation/networking/multi-pf-netdev.rst
@@ -0,0 +1,174 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+===============
+Multi-PF Netdev
+===============
+
+Contents
+========
+
+- `Background`_
+- `Overview`_
+- `mlx5 implementation`_
+- `Channels distribution`_
+- `Observability`_
+- `Steering`_
+- `Mutually exclusive features`_
+
+Background
+==========
+
+The Multi-PF NIC technology enables several CPUs within a multi-socket server to connect directly to
+the network, each through its own dedicated PCIe interface. Through either a connection harness that
+splits the PCIe lanes between two cards or by bifurcating a PCIe slot for a single card. This
+results in eliminating the network traffic traversing over the internal bus between the sockets,
+significantly reducing overhead and latency, in addition to reducing CPU utilization and increasing
+network throughput.
+
+Overview
+========
+
+The feature adds support for combining multiple PFs of the same port in a Multi-PF environment under
+one netdev instance. It is implemented in the netdev layer. Lower-layer instances like pci func,
+sysfs entry, and devlink are kept separate.
+Passing traffic through different devices belonging to different NUMA sockets saves cross-NUMA
+traffic and allows apps running on the same netdev from different NUMAs to still feel a sense of
+proximity to the device and achieve improved performance.
+
+mlx5 implementation
+===================
+
+Multi-PF or Socket-direct in mlx5 is achieved by grouping PFs together which belong to the same
+NIC and has the socket-direct property enabled, once all PFs are probed, we create a single netdev
+to represent all of them, symmetrically, we destroy the netdev whenever any of the PFs is removed.
+
+The netdev network channels are distributed between all devices, a proper configuration would utilize
+the correct close NUMA node when working on a certain app/CPU.
+
+We pick one PF to be a primary (leader), and it fills a special role. The other devices
+(secondaries) are disconnected from the network at the chip level (set to silent mode). In silent
+mode, no south <-> north traffic flowing directly through a secondary PF. It needs the assistance of
+the leader PF (east <-> west traffic) to function. All Rx/Tx traffic is steered through the primary
+to/from the secondaries.
+
+Currently, we limit the support to PFs only, and up to two PFs (sockets).
+
+Channels distribution
+=====================
+
+We distribute the channels between the different PFs to achieve local NUMA node performance
+on multiple NUMA nodes.
+
+Each combined channel works against one specific PF, creating all its datapath queues against it. We
+distribute channels to PFs in a round-robin policy.
+
+::
+
+        Example for 2 PFs and 5 channels:
+        +--------+--------+
+        | ch idx | PF idx |
+        +--------+--------+
+        |    0   |    0   |
+        |    1   |    1   |
+        |    2   |    0   |
+        |    3   |    1   |
+        |    4   |    0   |
+        +--------+--------+
+
+
+The reason we prefer round-robin is, it is less influenced by changes in the number of channels. The
+mapping between a channel index and a PF is fixed, no matter how many channels the user configures.
+As the channel stats are persistent across channel's closure, changing the mapping every single time
+would turn the accumulative stats less representing of the channel's history.
+
+This is achieved by using the correct core device instance (mdev) in each channel, instead of them
+all using the same instance under "priv->mdev".
+
+Observability
+=============
+The relation between PF, irq, napi, and queue can be observed via netlink spec::
+
+  $ ./tools/net/ynl/pyynl/cli.py --spec Documentation/netlink/specs/netdev.yaml --dump queue-get --json='{"ifindex": 13}'
+  [{'id': 0, 'ifindex': 13, 'napi-id': 539, 'type': 'rx'},
+   {'id': 1, 'ifindex': 13, 'napi-id': 540, 'type': 'rx'},
+   {'id': 2, 'ifindex': 13, 'napi-id': 541, 'type': 'rx'},
+   {'id': 3, 'ifindex': 13, 'napi-id': 542, 'type': 'rx'},
+   {'id': 4, 'ifindex': 13, 'napi-id': 543, 'type': 'rx'},
+   {'id': 0, 'ifindex': 13, 'napi-id': 539, 'type': 'tx'},
+   {'id': 1, 'ifindex': 13, 'napi-id': 540, 'type': 'tx'},
+   {'id': 2, 'ifindex': 13, 'napi-id': 541, 'type': 'tx'},
+   {'id': 3, 'ifindex': 13, 'napi-id': 542, 'type': 'tx'},
+   {'id': 4, 'ifindex': 13, 'napi-id': 543, 'type': 'tx'}]
+
+  $ ./tools/net/ynl/pyynl/cli.py --spec Documentation/netlink/specs/netdev.yaml --dump napi-get --json='{"ifindex": 13}'
+  [{'id': 543, 'ifindex': 13, 'irq': 42},
+   {'id': 542, 'ifindex': 13, 'irq': 41},
+   {'id': 541, 'ifindex': 13, 'irq': 40},
+   {'id': 540, 'ifindex': 13, 'irq': 39},
+   {'id': 539, 'ifindex': 13, 'irq': 36}]
+
+Here you can clearly observe our channels distribution policy::
+
+  $ ls /proc/irq/{36,39,40,41,42}/mlx5* -d -1
+  /proc/irq/36/mlx5_comp0@pci:0000:08:00.0
+  /proc/irq/39/mlx5_comp0@pci:0000:09:00.0
+  /proc/irq/40/mlx5_comp1@pci:0000:08:00.0
+  /proc/irq/41/mlx5_comp1@pci:0000:09:00.0
+  /proc/irq/42/mlx5_comp2@pci:0000:08:00.0
+
+Steering
+========
+Secondary PFs are set to "silent" mode, meaning they are disconnected from the network.
+
+In Rx, the steering tables belong to the primary PF only, and it is its role to distribute incoming
+traffic to other PFs, via cross-vhca steering capabilities. Still maintain a single default RSS table,
+that is capable of pointing to the receive queues of a different PF.
+
+In Tx, the primary PF creates a new Tx flow table, which is aliased by the secondaries, so they can
+go out to the network through it.
+
+In addition, we set default XPS configuration that, based on the CPU, selects an SQ belonging to the
+PF on the same node as the CPU.
+
+XPS default config example:
+
+NUMA node(s):          2
+NUMA node0 CPU(s):     0-11
+NUMA node1 CPU(s):     12-23
+
+PF0 on node0, PF1 on node1.
+
+- /sys/class/net/eth2/queues/tx-0/xps_cpus:000001
+- /sys/class/net/eth2/queues/tx-1/xps_cpus:001000
+- /sys/class/net/eth2/queues/tx-2/xps_cpus:000002
+- /sys/class/net/eth2/queues/tx-3/xps_cpus:002000
+- /sys/class/net/eth2/queues/tx-4/xps_cpus:000004
+- /sys/class/net/eth2/queues/tx-5/xps_cpus:004000
+- /sys/class/net/eth2/queues/tx-6/xps_cpus:000008
+- /sys/class/net/eth2/queues/tx-7/xps_cpus:008000
+- /sys/class/net/eth2/queues/tx-8/xps_cpus:000010
+- /sys/class/net/eth2/queues/tx-9/xps_cpus:010000
+- /sys/class/net/eth2/queues/tx-10/xps_cpus:000020
+- /sys/class/net/eth2/queues/tx-11/xps_cpus:020000
+- /sys/class/net/eth2/queues/tx-12/xps_cpus:000040
+- /sys/class/net/eth2/queues/tx-13/xps_cpus:040000
+- /sys/class/net/eth2/queues/tx-14/xps_cpus:000080
+- /sys/class/net/eth2/queues/tx-15/xps_cpus:080000
+- /sys/class/net/eth2/queues/tx-16/xps_cpus:000100
+- /sys/class/net/eth2/queues/tx-17/xps_cpus:100000
+- /sys/class/net/eth2/queues/tx-18/xps_cpus:000200
+- /sys/class/net/eth2/queues/tx-19/xps_cpus:200000
+- /sys/class/net/eth2/queues/tx-20/xps_cpus:000400
+- /sys/class/net/eth2/queues/tx-21/xps_cpus:400000
+- /sys/class/net/eth2/queues/tx-22/xps_cpus:000800
+- /sys/class/net/eth2/queues/tx-23/xps_cpus:800000
+
+Mutually exclusive features
+===========================
+
+The nature of Multi-PF, where different channels work with different PFs, conflicts with
+stateful features where the state is maintained in one of the PFs.
+For example, in the TLS device-offload feature, special context objects are created per connection
+and maintained in the PF.  Transitioning between different RQs/SQs would break the feature. Hence,
+we disable this combination for now.