Re: [PATCH] bpf: Convert lpm_trie::lock to 'raw_spinlock_t'

[Thomas Weißschuh]

On 2024-11-16 08:01:49-0800, Alexei Starovoitov wrote:
> On Sat, Nov 16, 2024 at 1:21 AM Sebastian Andrzej Siewior
> <bigeasy@xxxxxxxxxxxxx> wrote:
> >
> > On 2024-11-15 23:29:31 [+0100], Thomas Gleixner wrote:
> > > IIRC, BPF has it's own allocator which can be used everywhere.
> >
> > Thomas Weißschuh made something. It appears to work. Need to take a
> > closer look.
> 
> Any more details?
> bpf_mem_alloc is a stop gap.

It is indeed using bpf_mem_alloc.
It is a fairly straightforward conversion, using one cache for
intermediate and one for non-intermediate nodes.

I'll try to send it early next week.

> As Vlastimil Babka suggested long ago:
> https://lwn.net/Articles/974138/
> "...next on the target list is the special allocator used by the BPF
> subsystem. This allocator is intended to succeed in any calling
> context, including in non-maskable interrupts (NMIs). BPF maintainer
> Alexei Starovoitov is evidently in favor of this removal if SLUB is
> able to handle the same use cases..."
> 
> Here is the first step:
> https://lore.kernel.org/bpf/20241116014854.55141-1-alexei.starovoitov@xxxxxxxxx/