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Linux kernel source tree
7292af042b
Add a helper function to correctly handle the lockless
synchronization when the sender needs to block. The paradigm is
if (no_resources()) {
stop_queue();
barrier();
if (!no_resources())
restart_queue();
}
netif_subqueue_maybe_stop already handles the paradigm correctly, but
the code split the check for resources in three parts, the first one
(descriptors) followed the protocol, but the other two (completions and
tx_buf) were only doing the first part and so race prone.
Luckily netif_subqueue_maybe_stop macro already allows you to use a
function to evaluate the start/stop conditions so the fix only requires
the right helper function to evaluate all the conditions at once.
The patch removes idpf_tx_maybe_stop_common since it's no longer needed
and instead adjusts separately the conditions for singleq and splitq.
Note that idpf_tx_buf_hw_update doesn't need to check for resources
since that will be covered in idpf_tx_splitq_frame.
To reproduce:
Reduce the threshold for pending completions to increase the chances of
hitting this pause by changing your kernel:
drivers/net/ethernet/intel/idpf/idpf_txrx.h
-#define IDPF_TX_COMPLQ_OVERFLOW_THRESH(txcq) ((txcq)->desc_count >> 1)
+#define IDPF_TX_COMPLQ_OVERFLOW_THRESH(txcq) ((txcq)->desc_count >> 4)
Use pktgen to force the host to push small pkts very aggressively:
./pktgen_sample02_multiqueue.sh -i eth1 -s 100 -6 -d $IP -m $MAC \
-p 10000-10000 -t 16 -n 0 -v -x -c 64
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.