Re: [PATCH net-next 0/2] net/sched: don't wait for RCU when destroying qdisc lockdep keys

[Jakub Kicinski]

On Mon, 19 Oct 2026 10:02:23 -0700 Vlad Poenaru wrote:
> On kernels with CONFIG_PROVE_LOCKING, every qdisc except ingress, clsact
> and noqueue has a dynamic lockdep key, and destroying the qdisc calls
> lockdep_unregister_key(), which waits for an expedited RCU grace period.
> Replacing an mq root destroys one qdisc per TX queue under RTNL, so a
> single "tc qdisc replace dev eth0 root mq" waits for that many grace
> periods. Commit 7a3cedafccf8 ("lockdep: Speed up lockdep_unregister_key()
> with expedited RCU synchronization") made each wait shorter as a
> temporary workaround until hazard pointers are available.

## Form letter - net-next-closed

The merge window for Linux v7.4 has begun, and the net-next
tree is now closed for new drivers, features, code refactoring
and optimizations. We are currently accepting bug fixes only.

Please repost when net-next reopens. There is some uncertainty
about how long this merge window will last, so please check
https://netdev.bots.linux.dev/net-next.html
before reposting. net-next _may_ reopen on Nov 2nd.

See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#development-cycle
-- 
pw-bot: defer
pv-bot: closed