On Sun, Jun 04, 2023 at 02:22:30PM -0700, Song Liu wrote: > On Sun, Jun 4, 2023 at 11:02 AM Kent Overstreet > <kent.overstreet@xxxxxxxxx> wrote: > > > > On Fri, Jun 02, 2023 at 11:20:58AM -0700, Song Liu wrote: > > > IIUC, arm64 uses VMALLOC address space for BPF programs. The reason > > > is each BPF program uses at least 64kB (one page) out of the 128MB > > > address space. Puranjay Mohan (CC'ed) is working on enabling > > > bpf_prog_pack for arm64. Once this work is done, multiple BPF programs > > > will be able to share a page. Will this improvement remove the need to > > > specify a different address range for BPF programs? > > > > Can we please stop working on BPF specific sub page allocation and focus > > on doing this in mm/? This never should have been in BPF in the first > > place. > > That work is mostly independent of the allocator work we are discussing here. > The goal Puranjay's work is to enable the arm64 BPF JIT engine to use a > ROX allocator. The allocator could be the bpf_prog_pack allocator, or jitalloc, > or module_alloc_type. Puranjay is using bpf_prog_alloc for now. But once > jitalloc or module_alloc_type (either one) is merged, we will migrate BPF > JIT engines (x86_64 and arm64) to the new allocator and then tear down > bpf_prog_pack. > > Does this make sense? Yeah, as long as that's the plan. Maybe one of you could tell us what issues were preventing prog_pack from being used in the first place, it might be relevant - this is the time to get the new allocator API right.
