69dcb1e3bb
In advance of providing support for unaccepted memory, switch from using kmalloc() for allocating the Page State Change (PSC) structure to using a local variable that lives on the stack. This is needed to avoid a possible recursive call into set_pages_state() if the kmalloc() call requires (more) memory to be accepted, which would result in a hang. The current size of the PSC struct is 2,032 bytes. To make the struct more stack friendly, reduce the number of PSC entries from 253 down to 64, resulting in a size of 520 bytes. This is a nice compromise on struct size and total PSC requests while still allowing parallel PSC operations across vCPUs. If the reduction in PSC entries results in any kind of performance issue (that is not seen at the moment), use of a larger static PSC struct, with fallback to the smaller stack version, can be investigated. For more background info on this decision, see the subthread in the Link: tag below. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/lkml/658c455c40e8950cb046dd885dd19dc1c52d060a.1659103274.git.thomas.lendacky@amd.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.