In this commit, we make fib_validate_source() and __fib_validate_source()
return -reason instead of errno on error.
The return value of fib_validate_source can be -errno, 0, and 1. It's hard
to make fib_validate_source() return drop reasons directly.
The fib_validate_source() will return 1 if the scope of the source(revert)
route is HOST. And the __mkroute_input() will mark the skb with
IPSKB_DOREDIRECT in this case (combine with some other conditions). And
then, a REDIRECT ICMP will be sent in ip_forward() if this flag exists. We
can't pass this information to __mkroute_input if we make
fib_validate_source() return drop reasons.
Therefore, we introduce the wrapper fib_validate_source_reason() for
fib_validate_source(), which will return the drop reasons on error.
In the origin logic, LINUX_MIB_IPRPFILTER will be counted if
fib_validate_source() return -EXDEV. And now, we need to adjust it by
checking "reason == SKB_DROP_REASON_IP_RPFILTER". However, this will take
effect only after the patch "net: ip: make ip_route_input_noref() return
drop reasons", as we can't pass the drop reasons from
fib_validate_source() to ip_rcv_finish_core() in this patch.
Following new drop reasons are added in this patch:
SKB_DROP_REASON_IP_LOCAL_SOURCE
SKB_DROP_REASON_IP_INVALID_SOURCE
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Tariq Toukan says:
====================
mlx5 esw qos refactor and SHAMPO cleanup
This patchset for the mlx5 core and Eth drivers consists of 3 parts.
First patch by Patrisious improves the E-switch mode change operation.
The following 6 patches by Carolina introduce further refactoring for
the QoS handling, to set the foundation for future extensions.
In the following 5 patches by Dragos, we enhance the SHAMPO datapath
flow by simplifying some logic, and cleaning up the implementation.
====================
Link: https://patch.msgid.link/20241107194357.683732-1-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The current loop code was based on the assumption
that there can be page leftovers from previous function calls.
This patch changes the allocation loop to make it clearer how
pages get allocated every MLX5E_SHAMPO_WQ_HEADER_PER_PAGE headers.
This change has no functional implications.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-13-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The info array is used to store a pointer to the
dma address of the header and to the frag page. However,
this array is not really required:
- The frag page can be calculated from the header index
frag page index = header index / headers per page.
- The dma address can be calculated through a formula:
dma page address + header offset.
This series gets rid of the info array and uses the above
formulas instead.
The current_page_index was used in conjunction with the info array to
store page fragment indices. This variable is dropped as well.
There was no performance regression observed.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-12-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Now that the UMR allocation has been simplified, it is no longer
possible to have a leftover page from a previous call to
mlx5e_build_shampo_hd_umr().
This patch simplifies the code by switching the order of operations:
first take the frag page and then increment the index. This is more
straightforward and it also paves the way for dropping the info
array.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-11-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When calculating the index for the next frag page slot, the divisor is
incorrect: it should be the number of pages per queue not the number of
headers per queue. This is currently harmless because frag pages are not
used directly, but they are intermediated through the info array. But it
needs to be fixed as an upcoming patch will get rid of the info array.
This patch introduces a new pages per queue variable and plugs it in the
formula.
Now that this variable exists, additional code can be simplified in the
SHAMPO initialization code.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-10-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Allocating page fragments for header data split is currently
more complicated than it should be. That's because the number
of KSM entries allocated is not aligned to the number of headers
per page. This leads to having leftovers in the next allocation
which require additional accounting and needlessly complicated
code.
This patch aligns (down) the number of KSM entries in the
UMR WQE to the number of headers per page by:
1) Aligning the max number of entries allocated per UMR WQE
(max_ksm_entries) to MLX5E_SHAMPO_WQ_HEADER_PER_PAGE.
2) Aligning the total number of free headers to
MLX5E_SHAMPO_WQ_HEADER_PER_PAGE.
... and then it drops the extra accounting code from
mlx5e_build_shampo_hd_umr().
Although the number of entries allocated per UMR WQE is slightly
smaller due to aligning down, no performance impact was observed.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-9-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Refactor esw_qos_vport_enable to support more generic configurations,
allowing it to be reused for new vport node types in future patches.
This refactor includes a new way to change the vport parent node by
disabling the current setup and re-enabling it with the new parent.
This change sets the foundation for adapting configuration based on the
parent type in future patches.
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-8-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Fold the esw_qos_vport_enable function into operations for configuring
maximum and minimum rates, simplifying QoS logic. This change
consolidates enabling and updating the scheduling element
configuration, streamlining how vport QoS is initialized and adjusted.
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-7-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Introduce helper functions to create and destroy scheduling elements,
allowing flexible configuration for different scheduling element types.
The new helper functions streamline the process by centralizing error
handling and logging through esw_qos_sched_elem_op_warn, which now
accepts the operation type (create, destroy, or modify).
The changes also adjust the esw_qos_vport_enable and
mlx5_esw_qos_vport_disable functions to leverage the new generalized
create/destroy helpers.
The destroy functions now log errors with esw_warn without returning
them. This prevents unnecessary error handling since the node was
already destroyed and no further action is required from callers.
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-6-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Refactor esw_qos_sched_elem_config to set bitmasks only when max_rate
or bw_share values change, allowing the function to configure nodes
with only one of these parameters.
This enables more flexible usage for nodes where only one parameter
requires configuration.
Remove scattered assignments and checks to centralize them within this
function, removing the now redundant esw_qos_set_node_max_rate
entirely.
With this refactor, also remove the assignment of the vport scheduling
node max rate to the parent max rate for unlimited vports
(where max rate is set to zero), as firmware already handles this
behavior.
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-5-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Refactor max_rate and min_rate setting functions to operate on
mlx5_esw_sched_node, allowing for generalized handling of both vports
and nodes.
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-4-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This change updates esw_qos_normalize_min_rate to not return errors,
significantly simplifying the code.
Normalization failures are software bugs, and it's unnecessary to
handle them with rollback mechanisms. Instead,
`esw_qos_update_sched_node_bw_share` and `esw_qos_normalize_min_rate`
now return void, with any errors logged as warnings to indicate
potential software issues.
This approach avoids compensating for hidden bugs and removes error
handling from all places that perform normalization, streamlining
future patches.
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-3-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The E-switch mode was previously updated before removing and re-adding the
IB device, which could cause a temporary mismatch between the E-switch mode
and the IB device configuration.
To prevent this discrepancy, the IB device is now removed first, then
the E-switch mode is updated, and finally, the IB device is re-added.
This sequence ensures consistent alignment between the E-switch mode and
the IB device whenever the mode changes, regardless of the new mode value.
Signed-off-by: Patrisious Haddad <phaddad@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20241107194357.683732-2-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Check number of paths by fib_info_num_path(),
and update_or_create_fnhe() for every path.
Problem is that pmtu is cached only for the oif
that has received icmp message "need to frag",
other oifs will still try to use "default" iface mtu.
An example topology showing the problem:
| host1
+---------+
| dummy0 | 10.179.20.18/32 mtu9000
+---------+
+-----------+----------------+
+---------+ +---------+
| ens17f0 | 10.179.2.141/31 | ens17f1 | 10.179.2.13/31
+---------+ +---------+
| (all here have mtu 9000) |
+------+ +------+
| ro1 | 10.179.2.140/31 | ro2 | 10.179.2.12/31
+------+ +------+
| |
---------+------------+-------------------+------
|
+-----+
| ro3 | 10.10.10.10 mtu1500
+-----+
|
========================================
some networks
========================================
|
+-----+
| eth0| 10.10.30.30 mtu9000
+-----+
| host2
host1 have enabled multipath and
sysctl net.ipv4.fib_multipath_hash_policy = 1:
default proto static src 10.179.20.18
nexthop via 10.179.2.12 dev ens17f1 weight 1
nexthop via 10.179.2.140 dev ens17f0 weight 1
When host1 tries to do pmtud from 10.179.20.18/32 to host2,
host1 receives at ens17f1 iface an icmp packet from ro3 that ro3 mtu=1500.
And host1 caches it in nexthop exceptions cache.
Problem is that it is cached only for the iface that has received icmp,
and there is no way that ro3 will send icmp msg to host1 via another path.
Host1 now have this routes to host2:
ip r g 10.10.30.30 sport 30000 dport 443
10.10.30.30 via 10.179.2.12 dev ens17f1 src 10.179.20.18 uid 0
cache expires 521sec mtu 1500
ip r g 10.10.30.30 sport 30033 dport 443
10.10.30.30 via 10.179.2.140 dev ens17f0 src 10.179.20.18 uid 0
cache
So when host1 tries again to reach host2 with mtu>1500,
if packet flow is lucky enough to be hashed with oif=ens17f1 its ok,
if oif=ens17f0 it blackholes and still gets icmp msgs from ro3 to ens17f1,
until lucky day when ro3 will send it through another flow to ens17f0.
Signed-off-by: Vladimir Vdovin <deliran@verdict.gg>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20241108093427.317942-1-deliran@verdict.gg
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The netconsole selftest relies on the availability of the netdevsim module.
To ensure the test can run correctly, we need to check if the netdevsim
module is either loaded or built-in before proceeding.
Update the netconsole selftest to check for the existence of
the /sys/bus/netdevsim/new_device file before running the test. If the
file is not found, the test is skipped with an explanation that the
CONFIG_NETDEVSIM kernel config option may not be enabled.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20241108-netcon_selftest_deps-v1-1-1789cbf3adcd@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Russell King says:
====================
net: phylink: phylink_resolve() cleanups
This series does a bit of clean-up in phylink_resolve() to make the code
a little easier to follow.
Patch 1 moves the manual flow control setting in two of the switch
cases to after the switch().
Patch 2 changes the MLO_AN_FIXED case to be a simple if() statement,
reducing its indentation.
Patch 3 changes the MLO_AN_PHY case to also be a simple if() statment,
also reducing its indentation.
Patch 4 does the same for the last case.
Patch 5 reformats the code and comments for the reduced indentation,
making it easier to read.
====================
Link: https://patch.msgid.link/Zy411lVWe2SikuOs@shell.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Now that we have reduced the indentation level, clean up the code
formatting.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1t9RQz-002Ff5-EA@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The switch() statement doesn't sit very well with the preceeding if()
statements, so let's just convert everything to if()s. As a result of
the two preceding commits, there is now only one case in the switch()
statement. Remove the switch statement and reduce the code indentation.
Code reformatting will be in the following commit.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1t9RQu-002Fez-AA@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The switch() statement doesn't sit very well with the preceeding if()
statements, and results in excessive indentation that spoils code
readability. Continue cleaning this up by converting the MLO_AN_PHY
case to use an if() statmeent.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1t9RQp-002Fet-5W@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The switch() statement doesn't sit very well with the preceeding if()
statements, and results in excessive indentation that spoils code
readability. Begin cleaning this up by converting the MLO_AN_FIXED case
to an if() statement.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1t9RQk-002Fen-1A@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Move the handling of manual flow control configuration to a common
location during resolve. We currently evaluate this for all but
fixed links.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1t9RQe-002Feh-T1@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Joe Damato says:
====================
Suspend IRQs during application busy periods
This series introduces a new mechanism, IRQ suspension, which allows
network applications using epoll to mask IRQs during periods of high
traffic while also reducing tail latency (compared to existing
mechanisms, see below) during periods of low traffic. In doing so, this
balances CPU consumption with network processing efficiency.
Martin Karsten (CC'd) and I have been collaborating on this series for
several months and have appreciated the feedback from the community on
our RFC [1]. We've updated the cover letter and kernel documentation in
an attempt to more clearly explain how this mechanism works, how
applications can use it, and how it compares to existing mechanisms in
the kernel.
I briefly mentioned this idea at netdev conf 2024 (for those who were
there) and Martin described this idea in an earlier paper presented at
Sigmetrics 2024 [2].
~ The short explanation (TL;DR)
We propose adding a new napi config parameter: irq_suspend_timeout to
help balance CPU usage and network processing efficiency when using IRQ
deferral and napi busy poll.
If this parameter is set to a non-zero value *and* a user application
has enabled preferred busy poll on a busy poll context (via the
EPIOCSPARAMS ioctl introduced in commit 18e2bf0edf ("eventpoll: Add
epoll ioctl for epoll_params")), then application calls to epoll_wait
for that context will cause device IRQs and softirq processing to be
suspended as long as epoll_wait successfully retrieves data from the
NAPI. Each time data is retrieved, the irq_suspend_timeout is deferred.
If/when network traffic subsides and epoll_wait returns no data, IRQ
suspension is immediately reverted back to the existing
napi_defer_hard_irqs and gro_flush_timeout mechanism which was
introduced in commit 6f8b12d661 ("net: napi: add hard irqs deferral
feature")).
The irq_suspend_timeout serves as a safety mechanism. If userland takes
a long time processing data, irq_suspend_timeout will fire and restart
normal NAPI processing.
For a more in depth explanation, please continue reading.
~ Comparison with existing mechanisms
Interrupt mitigation can be accomplished in napi software, by setting
napi_defer_hard_irqs and gro_flush_timeout, or via interrupt coalescing
in the NIC. This can be quite efficient, but in both cases, a fixed
timeout (or packet count) needs to be configured. However, a fixed
timeout cannot effectively support both low- and high-load situations:
At low load, an application typically processes a few requests and then
waits to receive more input data. In this scenario, a large timeout will
cause unnecessary latency.
At high load, an application typically processes many requests before
being ready to receive more input data. In this case, a small timeout
will likely fire prematurely and trigger irq/softirq processing, which
interferes with the application's execution. This causes overhead, most
likely due to cache contention.
While NICs attempt to provide adaptive interrupt coalescing schemes,
these cannot properly take into account application-level processing.
An alternative packet delivery mechanism is busy-polling, which results
in perfect alignment of application processing and network polling. It
delivers optimal performance (throughput and latency), but results in
100% cpu utilization and is thus inefficient for below-capacity
workloads.
We propose to add a new packet delivery mode that properly alternates
between busy polling and interrupt-based delivery depending on busy and
idle periods of the application. During a busy period, the system
operates in busy-polling mode, which avoids interference. During an idle
period, the system falls back to interrupt deferral, but with a small
timeout to avoid excessive latencies. This delivery mode can also be
viewed as an extension of basic interrupt deferral, but alternating
between a small and a very large timeout.
This delivery mode is efficient, because it avoids softirq execution
interfering with application processing during busy periods. It can be
used with blocking epoll_wait to conserve cpu cycles during idle
periods. The effect of alternating between busy and idle periods is that
performance (throughput and latency) is very close to full busy polling,
while cpu utilization is lower and very close to interrupt mitigation.
~ Usage details
IRQ suspension is introduced via a per-NAPI configuration parameter that
controls the maximum time that IRQs can be suspended.
Here's how it is intended to work:
- The user application (or system administrator) uses the netdev-genl
netlink interface to set the pre-existing napi_defer_hard_irqs and
gro_flush_timeout NAPI config parameters to enable IRQ deferral.
- The user application (or system administrator) sets the proposed
irq_suspend_timeout parameter via the netdev-genl netlink interface
to a larger value than gro_flush_timeout to enable IRQ suspension.
- The user application issues the existing epoll ioctl to set the
prefer_busy_poll flag on the epoll context.
- The user application then calls epoll_wait to busy poll for network
events, as it normally would.
- If epoll_wait returns events to userland, IRQs are suspended for the
duration of irq_suspend_timeout.
- If epoll_wait finds no events and the thread is about to go to
sleep, IRQ handling using napi_defer_hard_irqs and gro_flush_timeout
is resumed.
As long as epoll_wait is retrieving events, IRQs (and softirq
processing) for the NAPI being polled remain disabled. When network
traffic reduces, eventually a busy poll loop in the kernel will retrieve
no data. When this occurs, regular IRQ deferral using gro_flush_timeout
for the polled NAPI is re-enabled.
Unless IRQ suspension is continued by subsequent calls to epoll_wait, it
automatically times out after the irq_suspend_timeout timer expires.
Regular deferral is also immediately re-enabled when the epoll context
is destroyed.
~ Usage scenario
The target scenario for IRQ suspension as packet delivery mode is a
system that runs a dominant application with substantial network I/O.
The target application can be configured to receive input data up to a
certain batch size (via epoll_wait maxevents parameter) and this batch
size determines the worst-case latency that application requests might
experience. Because packet delivery is suspended during the target
application's processing, the batch size also determines the worst-case
latency of concurrent applications using the same RX queue(s).
gro_flush_timeout should be set as small as possible, but large enough to
make sure that a single request is likely not being interfered with.
irq_suspend_timeout is largely a safety mechanism against misbehaving
applications. It should be set large enough to cover the processing of an
entire application batch, i.e., the factor between gro_flush_timeout and
irq_suspend_timeout should roughly correspond to the maximum batch size
that the target application would process in one go.
~ Important call out in the implementation
- Enabling per epoll-context preferred busy poll will now effectively
lead to a nonblocking iteration through napi_busy_loop, even when
busy_poll_usecs is 0. See patch 4.
~ Benchmark configs & descriptions
The changes were benchmarked with memcached [3] using the benchmarking
tool mutilate [4].
To facilitate benchmarking, a small patch [5] was applied to memcached
1.6.29 to allow setting per-epoll context preferred busy poll and other
settings via environment variables. Another small patch [6] was applied
to libevent to enable full busy-polling.
Multiple scenarios were benchmarked as described below and the scripts
used for producing these results can be found on github [7] (note: all
scenarios use NAPI-based traffic splitting via SO_INCOMING_ID by passing
-N to memcached):
- base:
- no other options enabled
- deferX:
- set defer_hard_irqs to 100
- set gro_flush_timeout to X,000
- napibusy:
- set defer_hard_irqs to 100
- set gro_flush_timeout to 200,000
- enable busy poll via the existing ioctl (busy_poll_usecs = 64,
busy_poll_budget = 64, prefer_busy_poll = true)
- fullbusy:
- set defer_hard_irqs to 100
- set gro_flush_timeout to 5,000,000
- enable busy poll via the existing ioctl (busy_poll_usecs = 1000,
busy_poll_budget = 64, prefer_busy_poll = true)
- change memcached's nonblocking epoll_wait invocation (via
libevent) to using a 1 ms timeout
- suspend0:
- set defer_hard_irqs to 0
- set gro_flush_timeout to 0
- set irq_suspend_timeout to 20,000,000
- enable busy poll via the existing ioctl (busy_poll_usecs = 0,
busy_poll_budget = 64, prefer_busy_poll = true)
- suspendX:
- set defer_hard_irqs to 100
- set gro_flush_timeout to X,000
- set irq_suspend_timeout to 20,000,000
- enable busy poll via the existing ioctl (busy_poll_usecs = 0,
busy_poll_budget = 64, prefer_busy_poll = true)
~ Benchmark results
Tested on:
Single socket AMD EPYC 7662 64-Core Processor
Hyperthreading disabled
4 NUMA Zones (NPS=4)
16 CPUs per NUMA zone (64 cores total)
2 x Dual port 100gbps Mellanox Technologies ConnectX-5 Ex EN NIC
The test machine is configured such that a single interface has 8 RX
queues. The queues' IRQs and memcached are pinned to CPUs that are
NUMA-local to the interface which is under test. The NIC's interrupt
coalescing configuration is left at boot-time defaults.
Results:
Results are shown below. The mechanism added by this series is
represented by the 'suspend' cases. Data presented shows a summary over
nearly 10 runs of each test case [8] using the scripts on github [7].
For latency, the median is shown. For throughput and CPU utilization,
the average is shown.
The results also include cycles-per-query (cpq) and
instruction-per-query (ipq) metrics, following the methodology proposed
in [2], to augment the CPU utilization numbers, which could be skewed
due to frequency scaling. We find that this does not appear to be the
case as CPU utilization and low-level metrics show similar trends.
These results were captured using the scripts on github [7] to
illustrate how this approach compares with other pre-existing
mechanisms. This data is not to be interpreted as scientific data
captured in a fully isolated lab setting, but instead as best effort,
illustrative information comparing and contrasting tradeoffs.
The absolute QPS results shift between submissions, but the
relative differences are equivalent. As patches are rebased,
several factors likely influence overall performance.
Compare:
- Throughput (MAX) and latencies of base vs suspend.
- CPU usage of napibusy and fullbusy during lower load (200K, 400K for
example) vs suspend.
- Latency of the defer variants vs suspend as timeout and load
increases.
- suspend0, which sets defer_hard_irqs and gro_flush_timeout to 0, has
nearly the same performance as the base case (this is FAQ item #1).
The overall takeaway is that the suspend variants provide a superior
combination of high throughput, low latency, and low cpu utilization
compared to all other variants. Each of the suspend variants works very
well, but some fine-tuning between latency and cpu utilization is still
possible by tuning the small timeout (gro_flush_timeout).
Note: we've reorganized the results to make comparison among testcases
with the same load easier.
testcase load qps avglat 95%lat 99%lat cpu cpq ipq
base 200K 199946 112 239 416 26 12973 11343
defer10 200K 199971 54 124 142 29 19412 17460
defer20 200K 199986 60 130 153 26 15644 14095
defer50 200K 200025 79 144 182 23 12122 11632
defer200 200K 199999 164 254 309 19 8923 9635
fullbusy 200K 199998 46 118 133 100 43658 23133
napibusy 200K 199983 100 237 277 56 24840 24716
suspend0 200K 200020 105 249 432 30 14264 11796
suspend10 200K 199950 53 123 141 32 19518 16903
suspend20 200K 200037 58 126 151 30 16426 14736
suspend50 200K 199961 73 136 177 26 13310 12633
suspend200 200K 199998 149 251 306 21 9566 10203
testcase load qps avglat 95%lat 99%lat cpu cpq ipq
base 400K 400014 139 269 707 41 9476 9343
defer10 400K 400016 59 133 166 53 13991 12989
defer20 400K 399952 67 140 172 47 12063 11644
defer50 400K 400007 87 162 198 39 9384 9880
defer200 400K 399979 181 274 330 31 7089 8430
fullbusy 400K 399987 50 123 156 100 21827 16037
napibusy 400K 400014 76 222 272 83 18185 16529
suspend0 400K 400015 127 350 776 47 10699 9603
suspend10 400K 400023 57 129 164 54 13758 13178
suspend20 400K 400043 62 135 169 49 12071 11826
suspend50 400K 400071 76 149 186 42 10011 10301
suspend200 400K 399961 154 269 327 34 7827 8774
testcase load qps avglat 95%lat 99%lat cpu cpq ipq
base 600K 599951 149 266 574 61 9265 8876
defer10 600K 600006 71 147 203 76 11866 10936
defer20 600K 600123 76 152 203 66 10430 10342
defer50 600K 600162 95 172 217 54 8526 9142
defer200 600K 599942 200 301 357 46 6977 8212
fullbusy 600K 599990 55 127 177 100 14551 13983
napibusy 600K 600035 63 160 250 96 13937 14140
suspend0 600K 599903 127 320 732 68 10166 8963
suspend10 600K 599908 63 137 192 69 10902 11100
suspend20 600K 599961 66 141 194 65 9976 10370
suspend50 600K 599973 80 159 204 57 8678 9381
suspend200 600K 600010 157 277 346 48 7133 8381
testcase load qps avglat 95%lat 99%lat cpu cpq ipq
base 800K 800039 181 300 536 87 9585 8304
defer10 800K 800038 181 530 939 96 10564 8970
defer20 800K 800029 112 225 329 90 10056 8935
defer50 800K 799999 120 208 296 82 9234 8562
defer200 800K 800066 227 338 401 63 7117 8129
fullbusy 800K 800040 61 134 190 100 10913 12608
napibusy 800K 799944 64 141 214 99 10828 12588
suspend0 800K 799911 126 248 509 85 9346 8498
suspend10 800K 800006 69 143 200 83 9410 9845
suspend20 800K 800120 74 150 207 78 8786 9454
suspend50 800K 799989 87 168 224 71 7946 8833
suspend200 800K 799987 160 292 357 62 6923 8229
testcase load qps avglat 95%lat 99%lat cpu cpq ipq
base 1000K 906879 4079 5751 6216 98 9496 7904
defer10 1000K 860849 3643 6274 6730 99 10040 8676
defer20 1000K 896063 3298 5840 6349 98 9620 8237
defer50 1000K 919782 2962 5513 5807 97 9284 7951
defer200 1000K 970941 3059 5348 5984 95 8593 7959
fullbusy 1000K 999950 70 150 207 100 8732 10777
napibusy 1000K 999996 78 154 223 100 8722 10656
suspend0 1000K 949706 2666 5770 6660 99 9071 8046
suspend10 1000K 1000024 80 160 220 92 8137 9035
suspend20 1000K 1000059 83 165 226 89 7850 8804
suspend50 1000K 999955 95 180 240 84 7411 8459
suspend200 1000K 999914 163 299 366 77 6833 8078
testcase load qps avglat 95%lat 99%lat cpu cpq ipq
base MAX 1037654 4184 5453 5810 100 8411 7938
defer10 MAX 905607 4840 6151 6380 100 9639 8431
defer20 MAX 986463 4455 5594 5796 100 8848 8110
defer50 MAX 1077030 4000 5073 5299 100 8104 7920
defer200 MAX 1040728 4152 5385 5765 100 8379 7849
fullbusy MAX 1247536 3518 3935 3984 100 6998 7930
napibusy MAX 1136310 3799 7756 9964 100 7670 7877
suspend0 MAX 1057509 4132 5724 6185 100 8253 7918
suspend10 MAX 1215147 3580 3957 4041 100 7185 7944
suspend20 MAX 1216469 3576 3953 3988 100 7175 7950
suspend50 MAX 1215871 3577 3961 4075 100 7181 7949
suspend200 MAX 1216882 3556 3951 3988 100 7175 7955
~ FAQ
- Why is a new parameter needed? Does irq_suspend_timeout override
gro_flush_timeout?
Using the suspend mechanism causes the system to alternate between
polling mode and irq-driven packet delivery. During busy periods,
irq_suspend_timeout overrides gro_flush_timeout and keeps the system
busy polling, but when epoll finds no events, the setting of
gro_flush_timeout and napi_defer_hard_irqs determine the next step.
There are essentially three possible loops for network processing and
packet delivery:
1) hardirq -> softirq -> napi poll; basic interrupt delivery
2) timer -> softirq -> napi poll; deferred irq processing
3) epoll -> busy-poll -> napi poll; busy looping
Loop 2 can take control from Loop 1, if gro_flush_timeout and
napi_defer_hard_irqs are set.
If gro_flush_timeout and napi_defer_hard_irqs are set, Loops 2 and
3 "wrestle" with each other for control. During busy periods,
irq_suspend_timeout is used as timer in Loop 2, which essentially
tilts this in favour of Loop 3.
If gro_flush_timeout and napi_defer_hard_irqs are not set, Loop 3
cannot take control from Loop 1.
Therefore, setting gro_flush_timeout and napi_defer_hard_irqs is the
recommended usage, because otherwise setting irq_suspend_timeout
might not have any discernible effect.
This is shown in the results above: compare suspend0 with the base
case. Note that the lack of napi_defer_hard_irqs and
gro_flush_timeout produce similar results for both, which encourages
the use of napi_defer_hard_irqs and gro_flush_timeout in addition to
irq_suspend_timeout.
- Can the new timeout value be threaded through the new epoll ioctl ?
It is possible, but presents challenges for userspace. User
applications must ensure that the file descriptors added to epoll
contexts have the same NAPI ID to support busy polling.
An epoll context is not permanently tied to any particular NAPI ID.
So, a user application could decide to clear the file descriptors
from the context and add a new set of file descriptors with a
different NAPI ID to the context. Busy polling would work as
expected, but the meaning of the suspend timeout becomes ambiguous
because IRQs are not inherently associated with epoll contexts, but
rather with the NAPI. The user program would need to reissue the
ioctl to set the irq_suspend_timeout, but the napi_defer_hard_irqs
and gro_flush_timeout settings would come from the NAPI's
napi_config (which are set either by sysfs or by netlink). Such an
interface seems awkard to use from a user perspective.
Further, IRQs are related to NAPIs, which is why they are stored in
the napi_config space. Putting the irq_suspend_timeout in
the epoll context while other IRQ deferral mechanisms remain in the
NAPI's napi_config space seems like an odd design choice.
We've opted to keep all of the IRQ deferral parameters together and
place the irq_suspend_timeout in napi_config. This has nice benefits
for userspace: if a user app were to remove all file descriptors
from an epoll context and add new file descriptors with a new NAPI ID,
the correct suspend timeout for that NAPI ID would be used automatically
without the user application needing to do anything (like re-issuing an
ioctl, for example). All IRQ deferral related parameters are in one
place and can all be set the same way: with netlink.
- Can irq suspend be built by combining NIC coalescing and
gro_flush_timeout ?
No. The problem is that the long timeout must engage if and only if
prefer-busy is active.
When using NIC coalescing for the short timeout (without
napi_defer_hard_irqs/gro_flush_timeout), an interrupt after an idle
period will trigger softirq, which will run napi polling. At this
point, prefer-busy is not active, so NIC interrupts would be
re-enabled. Then it is not possible for the longer timeout to
interject to switch control back to polling. In other words, only by
using the software timer for the short timeout, it is possible to
extend the timeout without having to reprogram the NIC timer or
reach down directly and disable interrupts.
Using gro_flush_timeout for the long timeout also has problems, for
the same underlying reason. In the current napi implementation,
gro_flush_timeout is not tied to prefer-busy. We'd either have to
change that and in the process modify the existing deferral
mechanism, or introduce a state variable to determine whether
gro_flush_timeout is used as long timeout for irq suspend or whether
it is used for its default purpose. In an earlier version, we did
try something similar to the latter and made it work, but it ends up
being a lot more convoluted than our current proposal.
- Isn't it already possible to combine busy looping with irq deferral?
Yes, in fact enabling irq deferral via napi_defer_hard_irqs and
gro_flush_timeout is a precondition for prefer_busy_poll to have an
effect. If the application also uses a tight busy loop with
essentially nonblocking epoll_wait (accomplished with a very short
timeout parameter), this is the fullbusy case shown in the results.
An application using blocking epoll_wait is shown as the napibusy
case in the results. It's a hybrid approach that provides limited
latency benefits compared to the base case and plain irq deferral,
but not as good as fullbusy or suspend.
~ Special thanks
Several people were involved in earlier stages of the development of this
mechanism whom we'd like to thank:
- Peter Cai (CC'd), for the initial kernel patch and his contributions
to the paper.
- Mohammadamin Shafie (CC'd), for testing various versions of the kernel
patch and providing helpful feedback.
Thanks,
Martin and Joe
[1]: https://lore.kernel.org/netdev/20240812125717.413108-1-jdamato@fastly.com/
[2]: https://doi.org/10.1145/3626780
[3]: https://github.com/memcached/memcached/blob/master/doc/napi_ids.txt
[4]: https://github.com/leverich/mutilate
[5]: https://raw.githubusercontent.com/martinkarsten/irqsuspend/main/patches/memcached.patch
[6]: https://raw.githubusercontent.com/martinkarsten/irqsuspend/main/patches/libevent.patch
[7]: https://github.com/martinkarsten/irqsuspend
[8]: https://github.com/martinkarsten/irqsuspend/tree/main/results
v8: https://lore.kernel.org/20241108045337.292905-1-jdamato@fastly.com
v7: https://lore.kernel.org/20241108023912.98416-1-jdamato@fastly.com
v6: https://lore.kernel.org/20241104215542.215919-1-jdamato@fastly.com
v5: https://lore.kernel.org/20241103052421.518856-1-jdamato@fastly.com
v4: https://lore.kernel.org/20241102005214.32443-1-jdamato@fastly.com
v3: https://lore.kernel.org/20241101004846.32532-1-jdamato@fastly.com
v2: https://lore.kernel.org/20241021015311.95468-1-jdamato@fastly.com
====================
Link: https://patch.msgid.link/20241109050245.191288-1-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Describe irq suspension, the epoll ioctls, and the tradeoffs of using
different gro_flush_timeout values.
Signed-off-by: Joe Damato <jdamato@fastly.com>
Co-developed-by: Martin Karsten <mkarsten@uwaterloo.ca>
Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://patch.msgid.link/20241109050245.191288-7-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add an epoll busy poll test using netdevsim.
This test is comprised of:
- busy_poller (via busy_poller.c)
- busy_poll_test.sh which loads netdevsim, sets up network namespaces,
and runs busy_poller to receive data and socat to send data.
The selftest tests two different scenarios:
- busy poll (the pre-existing version in the kernel)
- busy poll with suspend enabled (what this series adds)
The data transmit is a 1MiB temporary file generated from /dev/urandom
and the test is considered passing if the md5sum of the input file to
socat matches the md5sum of the output file from busy_poller.
netdevsim was chosen instead of veth due to netdevsim's support for
netdev-genl.
For now, this test uses the functionality that netdevsim provides. In the
future, perhaps netdevsim can be extended to emulate device IRQs to more
thoroughly test all pre-existing kernel options (like defer_hard_irqs)
and suspend.
Signed-off-by: Joe Damato <jdamato@fastly.com>
Co-developed-by: Martin Karsten <mkarsten@uwaterloo.ca>
Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20241109050245.191288-6-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When events are reported to userland and prefer_busy_poll is set, irqs
are temporarily suspended using napi_suspend_irqs.
If no events are found and ep_poll would go to sleep, irq suspension is
cancelled using napi_resume_irqs.
Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Co-developed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Joe Damato <jdamato@fastly.com>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Link: https://patch.msgid.link/20241109050245.191288-5-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Setting prefer_busy_poll now leads to an effectively nonblocking
iteration though napi_busy_loop, even when busy_poll_usecs is 0.
Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Co-developed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Joe Damato <jdamato@fastly.com>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Link: https://patch.msgid.link/20241109050245.191288-4-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The napi_suspend_irqs routine bootstraps irq suspension by elongating
the defer timeout to irq_suspend_timeout.
The napi_resume_irqs routine effectively cancels irq suspension by
forcing the napi to be scheduled immediately.
Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Co-developed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Joe Damato <jdamato@fastly.com>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Link: https://patch.msgid.link/20241109050245.191288-3-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a per-NAPI IRQ suspension parameter, which can be get/set with
netdev-genl.
This patch doesn't change any behavior but prepares the code for other
changes in the following commits which use irq_suspend_timeout as a
timeout for IRQ suspension.
Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca>
Co-developed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Joe Damato <jdamato@fastly.com>
Tested-by: Joe Damato <jdamato@fastly.com>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Link: https://patch.msgid.link/20241109050245.191288-2-jdamato@fastly.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Serialization of PHC read with FW reset mechanism uses ptp_lock which
also protects timecounter updates. This means we cannot grab it when
called from bnxt_cc_read(). Let's move locking into different function.
Fixes: 6c0828d00f ("bnxt_en: replace PTP spinlock with seqlock")
Signed-off-by: Vadim Fedorenko <vadfed@meta.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Link: https://patch.msgid.link/20241107214917.2980976-1-vadfed@meta.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Kuniyuki Iwashima says:
====================
rtnetlink: Convert rtnl_newlink() to per-netns RTNL.
Patch 1 - 3 removes __rtnl_link_unregister and protect link_ops by
its dedicated mutex to move synchronize_srcu() out of RTNL scope.
Patch 4 introduces struct rtnl_nets and helper functions to acquire
multiple per-netns RTNL in rtnl_newlink().
Patch 5 - 8 are to prefetch the peer device's netns in rtnl_newlink().
Patch 9 converts rtnl_newlink() to per-netns RTNL.
Patch 10 pushes RTNL down to rtnl_dellink() and rtnl_setlink(), but
the conversion will not be completed unless we support cases with
peer/upper/lower devices.
I confirmed v3 survived ./rtnetlink.sh; rmmod netdevsim.ko; without
lockdep splat.
v3: https://lore.kernel.org/20241107022900.70287-1-kuniyu@amazon.com
v2: https://lore.kernel.org/20241106022432.13065-1-kuniyu@amazon.com
v1: https://lore.kernel.org/20241105020514.41963-1-kuniyu@amazon.com
====================
Link: https://patch.msgid.link/20241108004823.29419-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Currently, rtnl_setlink() and rtnl_dellink() cannot be fully converted
to per-netns RTNL due to a lack of handling peer/lower/upper devices in
different netns.
For example, when we change a device in rtnl_setlink() and need to
propagate that to its upper devices, we want to avoid acquiring all netns
locks, for which we do not know the upper limit.
The same situation happens when we remove a device.
rtnl_dellink() could be transformed to remove a single device in the
requested netns and delegate other devices to per-netns work, and
rtnl_setlink() might be ?
Until we come up with a better idea, let's use a new flag
RTNL_FLAG_DOIT_PERNET_WIP for rtnl_dellink() and rtnl_setlink().
This will unblock converting RTNL users where such devices are not related.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241108004823.29419-11-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Now, we are ready to convert rtnl_newlink() to per-netns RTNL;
rtnl_link_ops is protected by SRCU and netns is prefetched in
rtnl_newlink().
Let's register rtnl_newlink() with RTNL_FLAG_DOIT_PERNET and
push RTNL down as rtnl_nets_lock().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241108004823.29419-10-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
For per-netns RTNL, we need to prefetch the peer device's netns.
Let's set rtnl_link_ops.peer_type and accordingly remove duplicated
validation in ->newlink().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241108004823.29419-9-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
For per-netns RTNL, we need to prefetch the peer device's netns.
Let's set rtnl_link_ops.peer_type and accordingly remove duplicated
validation in ->newlink().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241108004823.29419-8-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
For per-netns RTNL, we need to prefetch the peer device's netns.
Let's set rtnl_link_ops.peer_type and accordingly remove duplicated
validation in ->newlink().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241108004823.29419-7-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In ops->newlink(), veth, vxcan, and netkit call rtnl_link_get_net() with
a net pointer, which is the first argument of ->newlink().
rtnl_link_get_net() could return another netns based on IFLA_NET_NS_PID
and IFLA_NET_NS_FD in the peer device's attributes.
We want to get it and fill rtnl_nets->nets[] in advance in rtnl_newlink()
for per-netns RTNL.
All of the three get the peer netns in the same way:
1. Call rtnl_nla_parse_ifinfomsg()
2. Call ops->validate() (vxcan doesn't have)
3. Call rtnl_link_get_net_tb()
Let's add a new field peer_type to struct rtnl_link_ops and prefetch
netns in the peer ifla to add it to rtnl_nets in rtnl_newlink().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241108004823.29419-6-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
rtnl_newlink() needs to hold 3 per-netns RTNL: 2 for a new device
and 1 for its peer.
We will add rtnl_nets_lock() later, which performs the nested locking
based on struct rtnl_nets, which has an array of struct net pointers.
rtnl_nets_add() adds a net pointer to the array and sorts it so that
rtnl_nets_lock() can simply acquire per-netns RTNL from array[0] to [2].
Before calling rtnl_nets_add(), get_net() must be called for the net,
and rtnl_nets_destroy() will call put_net() for each.
Let's apply the helpers to rtnl_newlink().
When CONFIG_DEBUG_NET_SMALL_RTNL is disabled, we do not call
rtnl_net_lock() thus do not care about the array order, so
rtnl_net_cmp_locks() returns -1 so that the loop in rtnl_nets_add()
can be optimised to NOP.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://patch.msgid.link/20241108004823.29419-5-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
link_ops is protected by link_ops_mutex and no longer needs RTNL,
so we have no reason to have __rtnl_link_register() separately.
Let's remove it and call rtnl_link_register() from ifb.ko and
dummy.ko.
Note that both modules' init() work on init_net only, so we need
not export pernet_ops_rwsem and can use rtnl_net_lock() there.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20241108004823.29419-4-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
rtnl_link_unregister() holds RTNL and calls synchronize_srcu(),
but rtnl_newlink() will acquire SRCU frist and then RTNL.
Then, we need to unlink ops and call synchronize_srcu() outside
of RTNL to avoid the deadlock.
rtnl_link_unregister() rtnl_newlink()
---- ----
lock(rtnl_mutex);
lock(&ops->srcu);
lock(rtnl_mutex);
sync(&ops->srcu);
Let's move as such and add a mutex to protect link_ops.
Now, link_ops is protected by its dedicated mutex and
rtnl_link_register() no longer needs to hold RTNL.
While at it, we move the initialisation of ops->dellink and
ops->srcu out of the mutex scope.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20241108004823.29419-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
rtnl_link_unregister() holds RTNL and calls __rtnl_link_unregister(),
where we call synchronize_srcu() to wait inflight RTM_NEWLINK requests
for per-netns RTNL.
We put synchronize_srcu() in __rtnl_link_unregister() due to ifb.ko
and dummy.ko.
However, rtnl_newlink() will acquire SRCU before RTNL later in this
series. Then, lockdep will detect the deadlock:
rtnl_link_unregister() rtnl_newlink()
---- ----
lock(rtnl_mutex);
lock(&ops->srcu);
lock(rtnl_mutex);
sync(&ops->srcu);
To avoid the problem, we must call synchronize_srcu() before RTNL in
rtnl_link_unregister().
As a preparation, let's remove __rtnl_link_unregister().
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20241108004823.29419-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stanislav Fomichev says:
====================
selftests: ncdevmem: Add ncdevmem to ksft
The goal of the series is to simplify and make it possible to use
ncdevmem in an automated way from the ksft python wrapper.
ncdevmem is slowly mutated into a state where it uses stdout
to print the payload and the python wrapper is added to
make sure the arrived payload matches the expected one.
====================
Link: https://patch.msgid.link/20241107181211.3934153-1-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Only RX side for now and small message to test the setup.
In the future, we can extend it to TX side and to testing
both sides with a couple of megs of data.
make \
-C tools/testing/selftests \
TARGETS="drivers/hw/net" \
install INSTALL_PATH=~/tmp/ksft
scp ~/tmp/ksft ${HOST}:
scp ~/tmp/ksft ${PEER}:
cfg+="NETIF=${DEV}\n"
cfg+="LOCAL_V6=${HOST_IP}\n"
cfg+="REMOTE_V6=${PEER_IP}\n"
cfg+="REMOTE_TYPE=ssh\n"
cfg+="REMOTE_ARGS=root@${PEER}\n"
echo -e "$cfg" | ssh root@${HOST} "cat > ksft/drivers/net/net.config"
ssh root@${HOST} "cd ksft && ./run_kselftest.sh -t drivers/net:devmem.py"
Reviewed-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20241107181211.3934153-13-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is where all the tests that depend on the HW functionality live in
and this is where the automated test is gonna be added in the next
patch.
Reviewed-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20241107181211.3934153-12-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This will be used as a 'probe' mode in the selftest to check whether
the device supports the devmem or not. Use hard-coded queue layout
(two last queues) and prevent user from passing custom -q and/or -t.
Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20241107181211.3934153-11-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use single last queue of the device and probe it dynamically.
Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20241107181211.3934153-10-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In the next patch the hard-coded queue numbers are gonna be removed.
So introduce some initial support for ethtool YNL and use
it to enable header split.
Also, tcp-data-split requires latest ethtool which is unlikely
to be present in the distros right now.
(ideally, we should not shell out to ethtool at all).
Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20241107181211.3934153-9-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ntuple off/on might be not enough to do it on all NICs.
Add a bunch of shell crap to explicitly remove the rules.
Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20241107181211.3934153-8-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use dualstack socket to support both v4 and v6. v4-mapped-v6 address
can be used to do v4.
Reviewed-by: Mina Almasry <almasrymina@google.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20241107181211.3934153-7-sdf@fomichev.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
