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| author | Song Liu <[email protected]> | 2020-10-29 07:19:25 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <[email protected]> | 2020-10-30 20:03:29 +0000 |
| commit | 20b6cc34ea74b6a84599c1f8a70f3315b56a1883 (patch) | |
| tree | d3a5f38e379c3a12c5592aeec15e1806e9a26403 /tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c | |
| parent | bpf: Use separate lockdep class for each hashtab (diff) | |
| download | kernel-20b6cc34ea74b6a84599c1f8a70f3315b56a1883.tar.gz kernel-20b6cc34ea74b6a84599c1f8a70f3315b56a1883.zip | |
bpf: Avoid hashtab deadlock with map_locked
If a hashtab is accessed in both non-NMI and NMI context, the system may
deadlock on bucket->lock. Fix this issue with percpu counter map_locked.
map_locked rejects concurrent access to the same bucket from the same CPU.
To reduce memory overhead, map_locked is not added per bucket. Instead,
8 percpu counters are added to each hashtab. buckets are assigned to these
counters based on the lower bits of its hash.
Signed-off-by: Song Liu <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c')
0 files changed, 0 insertions, 0 deletions