Re: [PATCH] rcuscale: Consolidate per-writer arrays into struct writer_state

[Davidlohr Bueso]

On Sun, 04 Oct 2026, Joel Fernandes wrote:

> The writer kthreads keep their state in five parallel arrays indexed by
> writer number: writer_tasks, writer_durations, writer_n_durations,
> writer_done and writer_freelists.  Each must be allocated, NULL-checked,
> freed and cleared separately, and the cleanup path needs several
> guards to cope with any one of them being missing.
>
> Collapse them into a single array of struct writer_state, holding the
> task pointer, the duration buffer, the measurement count, the done flag
> and the existing struct writer_freelist.
>
> This reduces initialization to one allocation and one out-of-memory
> check, and cleanup to a single kfree().  As a side effect, this also
> fixes a leak: cleanup only ran its frees under "if (writer_tasks)", so
> if the writer_tasks allocation failed while a later allocation (for
> example writer_durations or writer_n_durations) still succeeded, those
> already-allocated arrays were never freed.  With a single allocation,
> that partial-allocation state can no longer occur.
>
> Assisted-by: Codex
> Fixes: 8704baab9bc8 ("rcutorture: Add RCU grace-period performance tests")
> Signed-off-by: Joel Fernandes <joelagnelf@xxxxxxxxxx>

Acked-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>