f03d253ba7
[ Upstream commit 0c80f9e165f8f9cca743d7b6cbdb54362da297e0 ] Currently, everytime an information needs to be fetched from the PPTT, the table is mapped via acpi_get_table() and unmapped after the use via acpi_put_table() which is fine. However we do this at runtime especially when the CPU is hotplugged out and plugged in back since we re-populate the cache topology and other information. However, with the support to fetch LLC information from the PPTT in the cpuhotplug path which is executed in the atomic context, it is preferred to avoid mapping and unmapping of the PPTT for every single use as the acpi_get_table() might sleep waiting for a mutex. In order to avoid the same, the table is needs to just mapped once on the boot CPU and is never unmapped allowing it to be used at runtime with out the hassle of mapping and unmapping the table. Reported-by: Guenter Roeck <linux@roeck-us.net> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> -- Hi Rafael, Sorry to bother you again on this PPTT changes. Guenter reported an issue with lockdep enabled in -next that include my cacheinfo/arch_topology changes to utilise LLC from PPTT in the CPU hotplug path. Please ack the change once you are happy so that I can get it merged with other fixes via Greg's tree. Regards, Sudeep Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Link: https://lore.kernel.org/r/20220720-arch_topo_fixes-v3-2-43d696288e84@arm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.