Hi Jiri, On Fri, Jan 13, 2023 at 5:26 AM Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > On Thu, Jan 12, 2023 at 01:40:07PM -0800, Namhyung Kim wrote: > > Hello, > > > > The perf_prepare_sample() is to fill the perf sample data and update the > > header info before sending it to the ring buffer. But we want to use it > > for BPF overflow handler so that it can access the sample data to filter > > relevant ones. > > > > Changes in v2) > > * the layout change is merged > > * reduce branches using __cond_set (PeterZ) > > * add helpers to set dynamic sample data (PeterZ) > > * introduce perf_prepare_header() (PeterZ) > > * call perf_prepare_sample() before bpf_overflow_handler unconditionally > > > > This means the perf_prepare_handler() can be called more than once. To > > avoid duplicate work, use the data->sample_flags and save the data size. > > > > I also added a few of helpers to set those information accordingly. > > But it looks some fields like REGS_USER, STACK_USER and AUX are saved in > > the perf_prepare_sample() so I didn't add the helpers for them. > > > > After than we can just check the filtered_sample_type flags begin zero > > to determine if it has more work. In that case, it needs to update the > > data->type since it's possible to miss when PMU driver sets all required > > sample flags before calling perf_prepare_sample(). > > > > The code is also available at 'perf/prepare-sample-v2' branch in > > > > git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git > > > > Thanks, > > Namhyung > > > > > > Cc: Song Liu <song@xxxxxxxxxx> > > Cc: bpf@xxxxxxxxxxxxxxx > > > > > > Namhyung Kim (8): > > perf/core: Save the dynamic parts of sample data size > > perf/core: Add perf_sample_save_callchain() helper > > perf/core: Add perf_sample_save_raw_data() helper > > perf/core: Add perf_sample_save_brstack() helper > > perf/core: Set data->sample_flags in perf_prepare_sample() > > perf/core: Do not pass header for sample id init > > perf/core: Introduce perf_prepare_header() > > perf/core: Call perf_prepare_sample() before running BPF > > lgtm, I ran the bpf selftests on top of that and it's ok Thanks for your review. I'll add your Acked-by and Tested-by in the v3. :) Thanks, Namhyung
