mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-29 07:02:29 -04:00
f1db825805
Pull trace ring-buffer updates from Steven Rostedt:
- Limit time interrupts are disabled in rb_check_pages()
rb_check_pages() is called after the ring buffer size is updated to
make sure that the ring buffer has not been corrupted. Commit
c2274b908d ("ring-buffer: Fix a race between readers and resize
checks") fixed a race with the check pages and simultaneous resizes
to the ring buffer by adding a raw_spin_lock_irqsave() around the
check operation. Although this was a simple fix, it would hold
interrupts disabled for non determinative amount of time. This could
harm PREEMPT_RT operations.
Instead, modify the logic by adding a counter when the buffer is
modified and to release the raw_spin_lock() at each iteration. It
checks the counter under the lock to see if a modification happened
during the loop, and if it did, it would restart the loop up to 3
times. After 3 times, it will simply exit the check, as it is
unlikely that would ever happen as buffer resizes are rare
occurrences.
- Replace some open coded str_low_high() with the helper
- Fix some documentation/comments
* tag 'trace-ring-buffer-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Correct a grammatical error in a comment
ring-buffer: Use str_low_high() helper in ring_buffer_producer()
ring-buffer: Reorganize kerneldoc parameter names
ring-buffer: Limit time with disabled interrupts in rb_check_pages()
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.