DAMON cannot be used from loadable modules since it is not exporting its symbols. This makes use of DAMON unnecessarily tedious. For example, we presented basic usge of DAMON at kernel summit 2021[1] by writing simple loadable DAMON application modules in live. Because the time was limited (10 minutes) and the coding was to be done step by step, we had to make a downstream commit that exports DAMON symbols. There were users asking why the source code is now not working. It was mainly due to the absence of the symbols export patch on their tree, but also due to the changed DAMON interfaces. There were also multiple users requesting support of loadable modules for easier deployment. There's no reason to avoid exporting DAMON symbols. However, it would be better to have concrete use cases of the symbols in the tree together, for better maintenance of the interface and the use cases. The kernels summit 2021's live-coded modules could be used for the purpose. Expose DAMON API modules for supporting the minimum modules and and add the kernel summit 2021's modules that updated for latest DAMON API under the samples directory. We will keep update of the sample modules. For exporting more symbols, requesters would be required to merge their modules using it in the tree together, or updsate the sample modules to use the newly-exporting symbols in reasonable and still simple ways. [1] https://linuxplumbersconf.org/event/11/contributions/984/ SeongJae Park (2): mm/damon/core: export symbols for supporting loadable modules samples: add DAMON sample kernel modules MAINTAINERS | 1 + mm/damon/core.c | 10 ++++ samples/Kconfig | 2 + samples/Makefile | 2 + samples/damon/Kconfig | 30 ++++++++++ samples/damon/Makefile | 3 + samples/damon/damon_sample_prcl.c | 98 +++++++++++++++++++++++++++++++ samples/damon/damon_sample_wsse.c | 80 +++++++++++++++++++++++++ 8 files changed, 226 insertions(+) create mode 100644 samples/damon/Kconfig create mode 100644 samples/damon/Makefile create mode 100644 samples/damon/damon_sample_prcl.c create mode 100644 samples/damon/damon_sample_wsse.c base-commit: 79cc930e5e3dc73c972d9e422b5e2ab3fe56dce5 -- 2.34.1
