Messages in this thread | | | Date | Fri, 20 Dec 2019 10:36:13 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/9] perf/core: Add PERF_SAMPLE_CGROUP feature |
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On Fri, Dec 20, 2019 at 01:32:46PM +0900, Namhyung Kim wrote: > The PERF_SAMPLE_CGROUP bit is to save (perf_event) cgroup information > in the sample. It will add a 64-bit id to identify current cgroup and > it's the file handle in the cgroup file system. Userspace should use > this information with PERF_RECORD_CGROUP event to match which cgroup > it belongs. > > I put it before PERF_SAMPLE_AUX for simplicity since it just needs a > 64-bit word. But if we want bigger samples, I can work on that > direction too. > > Cc: Tejun Heo <tj@kernel.org> > Cc: Li Zefan <lizefan@huawei.com> > Cc: Johannes Weiner <hannes@cmpxchg.org> > Signed-off-by: Namhyung Kim <namhyung@kernel.org> > ---
> @@ -6895,6 +6901,18 @@ void perf_prepare_sample(struct perf_event_header *header, > if (sample_type & PERF_SAMPLE_PHYS_ADDR) > data->phys_addr = perf_virt_to_phys(data->addr); > > + if (sample_type & PERF_SAMPLE_CGROUP) { > + u64 cgrp_id = 0; > +#ifdef CONFIG_CGROUP_PERF > + struct cgroup *cgrp; > + > + /* protected by RCU */ > + cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup; > + cgrp_id = cgroup_id(cgrp); > +#endif > + data->cgroup = cgrp_id; > + }
Would it make more sense to refuse SAMPLE_CGROUP if !CGROUP_PERF?
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