The PCI sysfs "config" file allows large reads, and the resulting PCI config reads can take several milliseconds to complete. Testing with the cyclictest [1] benchmark showed 5ms+ latencies. Add a schedule point in pci_read_config() to reduce the maximum latency. [1] https://git.kernel.org/pub/scm/linux/kernel/git/clrkwllms/rt-tests.git/ [bhelgaas: commit log] Link: https://lore.kernel.org/r/20200824052025.48362-1-benbjiang@tencent.com Reported-by: Bin Lai <robinlai@tencent.com> Signed-off-by: Jiang Biao <benbjiang@tencent.com> Signed-off-by: Bjorn Helgaas <bhelgaas@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.
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