Re: [RFC PATCH v3 0/9] futex: Add support task local hash maps.

Sebastian Andrzej Siewior
2024-12-03T18:27:43Z

On 2024-11-29 16:03:54 [+0100], Juri Lelli wrote:
> Hi Sebastian,
Hi Juri,

> On 15/11/24 17:58, Sebastian Andrzej Siewior wrote:
> > Hi,
> >
> > this is a follow up on
> > https://lore.kernel.org/ZwVOMgBMxrw7BU9A@jlelli-thinkpadt14gen4.remote.csb
> >
> > and adds support for task local futex_hash_bucket. It can be created via
> > prctl().
> >
> > This version supports resize at runtime. This fun part is limited is to
> > FUTEX_LOCK_PI which means any other waiter will break.
> >
> > I posted performance numbers of "perf bench futex hash"
> > https://lore.kernel.org/all/20241101110810.R3AnEqdu@linutronix.de/
>
> Performance looks generally good on our side as well. However, while
> testing the set manually with a debug enabled config (attached) I hit
> the following BUG (decoded) while booting the machine.

Thanks. That sounds good. Sorry for getting so late back. I posted v4
which fixes the bug you reported. The new version has auto resizing of
the hash table :)

Sebastian