Re: [RFC v2 PATCH 0/4] futex: Add support task local hash maps.
From: Sebastian Andrzej Siewior
Date: Mon Oct 28 2024 - 13:50:39 EST
On 2024-10-28 13:13:54 [+0100], To linux-kernel@xxxxxxxxxxxxxxx wrote:
> from time to time and I haven't seen it using the hashmap. Need to do
> more testing.
booted gnome and did a few things:
- Total allocations: 632
- tasks which never used their allocated futex hash: 2
gpg-agent and systemd-journal
- Tasks which did not terminate within the measurement: 85
This includes gpg-agent and systemd-journal
- Top5 users of the private hash:
- firefox-esr-3786 used 215985
- gnome-software-2343 used 121296
- chromium-3369 used 65796
- chromium-3209 used 34639
- Isolated used 34211
This looks like we could attach the private futex hashmap directly on
fork instead of delaying it to the first usage.
Side note: If someone is waiting for a thread to exit via pthread_join()
then glibc uses here futex() with op 0x109. I would have expected a
private flag.
Sebastian