tetragon: Add support for kprobe multi interface #79
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kkourt
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@kkourt I added the review changes and also added --disable-kprobe-multi option ;-) |
Add support to load data via MapLoad interfae into specific index. This way we can set up specific the array map elements. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding support to use specific element of config and filter map. Keeping the index initialized to zero for now, it will be set up by multi kprobe init code in following patches to read specific config and filter data. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
When we use single kprobe program instead of having one for each kprobe attachment, we need to make sure the retprobe_map id stays unique otherwise we can get mixed data. Adding extra id - function id - to the retprobe_map key to ensure that. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Moving global variables init to the top, so it's easier to add multi kprobe code in following changes. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding get_attach_cookie helper support, so it can be used in following changes. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding multi kprobe objects built from generic with __MULTI_KPROBE defined. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Loading proper index in multi kprobe objects from config map provided by user space configuration process. Once it's initialized it will read specific config/filter map element. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
The multi kprobe program needs to be placed in kprobe.multi section so it is loaded with special multi kprobe attach type. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding HasKprobeMulti that detects the support for multi kprobe link. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding support to attach kprobes with multi kprobe link if
there's more than one kprobe dfined and if there's kernel
support for multi kprobe link in kernel.
Adding both spec handler and loading code changes together.
There are following benhaviour changes to standard kprobes:
- only one program is loaded for all kprobes and it's
pinned under 'multi_kprobe' pin file
- only one program is loaded for all return kprobes and
pinned under 'multi_retkprobe' pin file
- there's single retprobe_map map instance
Each config needs to have extra element in 'config_map' and
'filter_map'. Limiting size of these to 100 at the moment,
this can be made bigger when we have wildcard support in.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding --disable-kprobe-multi option to allow user disable kprobe multi interface and have a choice to go with generic kprobes for whatever reason. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Multi kprobe support is still not widely around, skipping the object for now. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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Adding support to attach kprobes with multi kprobe link if
there's more than one kprobe defined and if there's kernel
support for multi kprobe link in kernel.
The multi kprobe interface attaches multiple kprobes much
faster than doing it one by one. Also we safe verifier time,
because the generic kprobe program is loaded just once.
perf stat -n for tracing tests:
There's no change to spec config, the multi kprobe is used
once we detect there's more then one kprobe defined.
Signed-off-by: Jiri Olsa jolsa@kernel.org