On Wed, Jul 26, 2023 at 4:38 AM Hou Tao <houtao@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> On 7/21/2023 10:31 AM, YiFei Zhu wrote:
> > On Thu, Jul 20, 2023 at 6:45 PM Hou Tao <houtao@xxxxxxxxxxxxxxx> wrote:
> >> On 7/21/2023 4:44 AM, YiFei Zhu wrote:
> >>> Sometimes during prefill all precpu chunks are full and atomic
> >>> __alloc_percpu_gfp would not allocate new chunks. This will cause
> >>> -ENOMEM immediately upon next unit_alloc.
> >>>
> >>> Prefill phase does not actually run in atomic context, so we can
> >>> use this fact to allocate non-atomically with GFP_KERNEL instead
> >>> of GFP_NOWAIT. This avoids the immediate -ENOMEM. Unfortunately
> >>> unit_alloc runs in atomic context, even from map item allocation in
> >>> syscalls, due to rcu_read_lock, so we can't do non-atomic
> >>> workarounds in unit_alloc.
> >>>
> >>> Fixes: 4ab67149f3c6 ("bpf: Add percpu allocation support to bpf_mem_alloc.")
> >>> Signed-off-by: YiFei Zhu <zhuyifei@xxxxxxxxxx>
> >> Make sense to me, so
> >>
> >> Acked-by: Hou Tao <houtao1@xxxxxxxxxx>
> >>
> >> But I don't know whether or not it is suitable for bpf tree.
> > I don't mind either way :) If changing to bpf-next requires a resend I
> > can do that too.
>
> Please resend and rebase the patch again bpf-next tree.
>
Will do. Should I drop the Fixes tag then?
YiFei Zhu
