09252177d5
Currently if a major timeout value is reached, but the minor value has
not been reached, an ETIMEOUT will not be sent back to the caller.
This can occur if the v4 server is not responding to requests and
retrans is configured larger than the default of two.
For example, A TCP mount with a configured timeout value of 50 and a
retransmission count of 3 to a v4 server which is not responding:
1. Initial value and increment set to 5s, maxval set to 20s, retries at 3
2. Major timeout is set to 20s, minor timeout set to 5s initially
3. xport_adjust_timeout() is called after 5s, retry with 10s timeout,
minor timeout is bumped to 10s
4. And again after another 10s, 15s total time with minor timeout set
to 15s
5. After 20s total time xport_adjust_timeout is called as major timeout is
reached, but skipped because the minor timeout is not reached
- After this time the cpu spins continually calling
xport_adjust_timeout() and returning 0 for 10 seconds.
As seen on perf sched:
39243.913182 [0005] mount.nfs[3794] 4607.938 0.017 9746.863
6. This continues until the 15s minor timeout condition is reached (in
this case for 10 seconds). After which the ETIMEOUT is processed
back to the caller, the cpu spinning stops, and normal operations
continue
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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 Restructured Text 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.