Hi Jiri, On Thu, Feb 9, 2023 at 6:25 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > On Wed, Feb 01, 2023 at 02:57:32PM +0100, Jiri Olsa wrote: > > hi, > > we have a use cases for bpf programs to use binary file's build id. > > > > After some attempts to add helpers/kfuncs [1] [2] Andrii had an idea [3] > > to store build id directly in the file object. That would solve our use > > case and might be beneficial for other profiling/tracing use cases with > > bpf programs. > > > > This RFC patchset adds new config CONFIG_FILE_BUILD_ID option, which adds > > build id object pointer to the file object when enabled. The build id is > > read/populated when the file is mmap-ed. > > > > I also added bpf and perf changes that would benefit from this. Thanks for working on this! > > > > I'm not sure what's the policy on adding stuff to file object, so apologies > > if that's out of line. I'm open to any feedback or suggestions if there's > > better place or way to do this. > > hi, > Matthew suggested on irc to consider inode for storing build id Yeah, that's my idea too. > > I tried that and it seems to have better stats wrt allocated build > id objects, because inode is being shared among file objects > > I took /proc/slabinfo output after running bpf tests > > - build id stored in file: > > # name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> : tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_slabs> <sharedavail> > build_id 668 775 160 25 1 : tunables 0 0 0 : slabdata 31 31 0 > > - build id stored in inode: > > # name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab> : tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_slabs> <sharedavail> > build_id 222 225 160 25 1 : tunables 0 0 0 : slabdata 9 9 0 Cool! > > > I'm stranger to inode/fs/mm code so I'll spend some time checking on > what I possibly broke in there before I send it, but I'd appreciate > any early feedback ;-) > > the code is in here: > git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git > inode_build_id > > I'll send another version with inode if there's no objection I'll take a look. Thanks, Namhyung > > > > [1] https://lore.kernel.org/bpf/20221108222027.3409437-1-jolsa@xxxxxxxxxx/ > > [2] https://lore.kernel.org/bpf/20221128132915.141211-1-jolsa@xxxxxxxxxx/ > > [3] https://lore.kernel.org/bpf/CAEf4BzaZCUoxN_X2ALXwQeFTCwtL17R4P_B_-hUCcidfyO2xyQ@xxxxxxxxxxxxxx/ > > --- > > Jiri Olsa (5): > > mm: Store build id in file object > > bpf: Use file object build id in stackmap > > perf: Use file object build id in perf_event_mmap_event > > selftests/bpf: Add file_build_id test > > selftests/bpf: Add iter_task_vma_buildid test > > > > fs/file_table.c | 3 +++ > > include/linux/buildid.h | 17 +++++++++++++++++ > > include/linux/fs.h | 3 +++ > > kernel/bpf/stackmap.c | 8 ++++++++ > > kernel/events/core.c | 43 +++++++++++++++++++++++++++++++++++++++---- > > lib/buildid.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ > > mm/Kconfig | 7 +++++++ > > mm/mmap.c | 15 +++++++++++++++ > > tools/testing/selftests/bpf/prog_tests/bpf_iter.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > tools/testing/selftests/bpf/prog_tests/file_build_id.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > tools/testing/selftests/bpf/progs/bpf_iter_task_vma_buildid.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ > > tools/testing/selftests/bpf/progs/file_build_id.c | 34 ++++++++++++++++++++++++++++++++++ > > tools/testing/selftests/bpf/trace_helpers.c | 35 +++++++++++++++++++++++++++++++++++ > > tools/testing/selftests/bpf/trace_helpers.h | 1 + > > 14 files changed, 413 insertions(+), 4 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/prog_tests/file_build_id.c > > create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_vma_buildid.c > > create mode 100644 tools/testing/selftests/bpf/progs/file_build_id.c
