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.
