asm-generic/io.h: Skip trace helpers if rwmmio events are disabled

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With `CONFIG_TRACE_MMIO_ACCESS=y`, the `{read,write}{b,w,l,q}{_relaxed}()`
mmio accessors unconditionally call `log_{post_}{read,write}_mmio()`
helpers, which in turn call the ftrace ops for `rwmmio` trace events

This adds a performance penalty per mmio accessor call, even when
`rwmmio` events are disabled at runtime (~80% overhead on local
measurement).

Guard these with `tracepoint_enabled()`.

Signed-off-by: Varad Gautam <varadgautam@google.com>
Fixes: 210031971c ("asm-generic/io: Add logging support for MMIO accessors")
Cc: stable@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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Varad Gautam 2025-03-30 16:42:29 +00:00 • committed by Arnd Bergmann

parent 8f5ae30d69

commit 8327bd4fcb

1 changed files with 66 additions and 32 deletions

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include/asm-generic/io.h

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