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2ebbe0308c
Add a Kconfig to allow architectures to opt-out of a TLB flush when a young page is aged, as invalidating TLB entries is not functionally required on most KVM-supported architectures. Stale TLB entries can result in false negatives and theoretically lead to suboptimal reclaim, but in practice all observations have been that the performance gained by skipping TLB flushes outweighs any performance lost by reclaiming hot pages. E.g. the primary MMUs for x86 RISC-V, s390, and PPC Book3S elide the TLB flush for ptep_clear_flush_young(), and arm64's MMU skips the trailing DSB that's required for ordering (presumably because there are optimizations related to eliding other TLB flushes when doing make-before-break). Link: https://lore.kernel.org/r/20241011021051.1557902-18-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.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 reStructuredText 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.