perf lock contention: Do not fail EEXIST for update

When it updates the lock stat for the first time, it needs to create an
element in the BPF hash map.

But if there's a concurrent thread waiting for the same lock (like for
rwsem or rwlock), it might race with the thread and possibly fail to
update with -EEXIST.

In that case, it can lookup the map again and put the data there instead
of failing.

Signed-off-by: Namhyung Kim <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Song Liu <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions