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251a7b3edc
x86_64 vmalloc() mappings are no longer "synchronized" among page tables via faulting since commit6eb82f9940("x86/mm: Pre-allocate P4D/PUD pages for vmalloc area"), since the corresponding P4D or PUD pages are now preallocated at boot, by preallocate_vmalloc_pages(). Drop the "lazily synchronized" description for less confusion. While this file is x86_64-specific, it is worth noting that things are different for x86_32, where vmalloc()-related changes to `init_mm.pgd` are synchronized to all page tables in the system during runtime, via arch_sync_kernel_mappings(). Unfortunately, this synchronization is subject to race condition, which is further handled via faulting, see vmalloc_fault(). See commit4819e15f74("x86/mm/32: Bring back vmalloc faulting on x86_32") for more details. Reviewed-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Peilin Ye <peilin.ye@bytedance.com> Reviewed-by: Joerg Roedel <jroedel@suse.de> Link: https://lore.kernel.org/r/20210818220123.2623-1-yepeilin.cs@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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.