Dan Williams
c91d713630
Commit6e9f05dc66("libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE") ...updated MAX_STRUCT_PAGE_SIZE to account for sizeof(struct page) potentially doubling in the case of CONFIG_KMSAN=y. Unfortunately this doubles the amount of capacity stolen from user addressable capacity for everyone, regardless of whether they are using the debug option. Revert that change, mandate that MAX_STRUCT_PAGE_SIZE never exceed 64, but allow for debug scenarios to proceed with creating debug sized page maps with a compile option to support debug scenarios. Note that this only applies to cases where the page map is permanent, i.e. stored in a reservation of the pmem itself ("--map=dev" in "ndctl create-namespace" terms). For the "--map=mem" case, since the allocation is ephemeral for the lifespan of the namespace, there are no explicit restriction. However, the implicit restriction, of having enough available "System RAM" to store the page map for the typically large pmem, still applies. Fixes:6e9f05dc66("libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE") Cc: <stable@vger.kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Marco Elver <elver@google.com> Reported-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Yu Zhao <yuzhao@google.com> Link: https://lore.kernel.org/r/167467815773.463042.7022545814443036382.stgit@dwillia2-xfh.jf.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.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.