[PATCH] arm64: clear_page[s] using memset
Catalin Marinas
catalin.marinas at arm.com
Thu Apr 2 13:57:08 PDT 2026
On Fri, Mar 06, 2026 at 09:57:50AM +0100, Linus Walleij wrote:
> There is no need to try to second-guess the compiler when
> clearing memory. Just call memset() like everyone else.
Hmm, that "like everyone else" made me think - why not move this to
generic code and only the 1-2 platforms that need their own should
override it? Could we do the same with copy_page()?
Sorry, more work all of a sudden ;).
> Since memset() already has an architecture-local MOPS
> optimization, we do not need to do anything else to preserve
> the MOPS optimization.
The custom clear_page() had the (very small) advantage that it can skip
the length/alignment checks as they are always page-size.
> While at it, implement the shorthand for directly calling
> the new prototype clear_pages() for larger page chunks.
>
> No performance regressions can be seen, the fastpath
> benchmarks differences are in the noise.
I assume the benchmarks ran on real hardware (had to ask, last time you
mentioned qemu ;)).
--
Catalin
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