On Tue, Dec 30, 2025 at 6:51 AM Jiri Olsa [off-list ref] wrote:

Using single ftrace_ops for direct calls update instead of allocating
ftrace_ops object for each trampoline.

With single ftrace_ops object we can use update_ftrace_direct_* api
that allows multiple ip sites updates on single ftrace_ops object.

Adding HAVE_SINGLE_FTRACE_DIRECT_OPS config option to be enabled on
each arch that supports this.

At the moment we can enable this only on x86 arch, because arm relies
on ftrace_ops object representing just single trampoline image (stored
in ftrace_ops::direct_call). Archs that do not support this will continue
to use *_ftrace_direct api.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 arch/x86/Kconfig        |   1 +
 kernel/bpf/trampoline.c | 220 ++++++++++++++++++++++++++++++++++------
 kernel/trace/Kconfig    |   3 +
 kernel/trace/ftrace.c   |   7 +-
 4 files changed, 200 insertions(+), 31 deletions(-)

As far as I can follow, everything looks reasonable

Acked-by: Andrii Nakryiko <andrii@kernel.org>


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