On Wed, Oct 20, 2021 at 3:48 AM <[email protected]> wrote:
>
> From: Anton Ivanov <[email protected]>
>
> Weak may fail for reasons unrelated to the comparison (not
> on x86, where these are practically equivalent).
>
> Thus, it can and should be used only in cases where there will
> be a repeat of the event which runs the code (in this case
> semaphore post).
>
> On non-x86 architectures using weak may result in a failed
> comparison without any more sem post events - a hang. Reported
> for arm, likely for other platforms where weak may fail.
>
> Reported-by: [email protected]
>
> Signed-off-by: Anton Ivanov <[email protected]>
Thanks. I applied this patch to the main branch and backported to
branch-21.09 and branch-21.06.
Numan
> ---
> lib/ovn-parallel-hmap.c | 2 +-
> ovs | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/lib/ovn-parallel-hmap.c b/lib/ovn-parallel-hmap.c
> index b8c7ac786..56ceed8e8 100644
> --- a/lib/ovn-parallel-hmap.c
> +++ b/lib/ovn-parallel-hmap.c
> @@ -267,7 +267,7 @@ ovn_run_pool_callback(struct worker_pool *pool,
> * (most likely acq_rel) to ensure that the main thread
> * sees all of the results produced by the worker.
> */
> - if (atomic_compare_exchange_weak(
> + if (atomic_compare_exchange_strong(
> &pool->controls[index].finished,
> &test,
> false)) {
> --
> 2.20.1
>
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