b11931e9ad
Allow PTE changes to avoid flushing the TLB when access permissions are being relaxed, the dirty bit is being set, and the accessed bit is being changed. Relaxing access permissions and setting dirty and accessed bits do not require a flush because the MMU will re-load the PTE and notice the updates (it may also cause a spurious fault). Clearing the accessed bit does not require a flush because of the imprecise PTE accessed bit accounting that is already performed, as documented in ptep_clear_flush_young(). This reduces TLB flushing for some mprotect(2) calls. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Link: https://lore.kernel.org/r/20220901110334.1618913-1-npiggin@gmail.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.