Pass external callchain entry to get_perf_callchain #6240
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added 2 commits
October 28, 2025 09:37
From BPF stack map, we want to use our own buffers to avoid unnecessary copy and ensure that the buffer will not be overwritten by other preemptive tasks. Peter suggested provide more flexible stack-sampling APIs, which can be used in BPF, and we can still use the perf callchain entry with the help of these APIs. The next patch will modify the BPF part. Signed-off-by: Peter Zijlstra <[email protected]> Signed-off-by: Tao Chen <[email protected]>
As Alexei noted, get_perf_callchain() return values may be reused if a task is preempted after the BPF program enters migrate disable mode. The perf_callchain_entres has a small stack of entries, and we can reuse it as follows: 1. get the perf callchain entry 2. BPF use... 3. put the perf callchain entry Signed-off-by: Tao Chen <[email protected]>
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Upstream branch: 8822409 |
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Pull request for series with
subject: Pass external callchain entry to get_perf_callchain
version: 4
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1016830