4812c54dc0
Booting w/ qemu without kvm, and with 64 cpus, I noticed we'd sometimes hung task watchdog splats in get_random_u32_below() when using the test-ww_mutex stress test. While entropy exhaustion is no longer an issue, the RNG may be slower early in boot. The test-ww_mutex code will spawn off 128 threads (2x cpus) and each thread will call get_random_u32_below() a number of times to generate a random order of the 16 locks. This intense use takes time and without kvm, qemu can be slow enough that we trip the hung task watchdogs. For this test, we don't need true randomness, just mixed up orders for testing ww_mutex lock acquisitions, so it changes the logic to use the prng instead, which takes less time and avoids the watchdgos. Feedback would be appreciated! Signed-off-by: John Stultz <jstultz@google.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230922043616.19282-2-jstultz@google.com
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.