On Thu, Nov 09, 2023 at 10:17:34PM -0800, Yonghong Song wrote:
> Kirill Shutemov reported significant percpu memory increase after booting
s/memory increase/memory consumption increase/ ?
> in 288-cpu VM ([1]) due to commit 41a5db8d8161 ("bpf: Add support for
> non-fix-size percpu mem allocation"). The percpu memory is increased
> from 111MB to 969MB. The number is from /proc/meminfo.
>
> I tried to reproduce the issue with my local VM which at most supports
> upto 255 cpus. With 252 cpus, without the above commit, the percpu memory
> immediately after boot is 57MB while with the above commit the percpu
> memory is 231MB.
>
> This is not good since so far percpu memory from bpf memory allocator
> is not widely used yet. Let us change pre-allocation in init stage
> to on-demand allocation when verifier detects there is a need of
> percpu memory for bpf program. With this change, percpu memory
> consumption after boot can be reduced signicantly.
>
> [1] https://lore.kernel.org/lkml/20231109154934.4saimljtqx625l3v@xxxxxxxxxxxxxxxxx/
>
> Fixes: 41a5db8d8161 ("bpf: Add support for non-fix-size percpu mem allocation")
> Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Reported-and-tested-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
--
Kiryl Shutsemau / Kirill A. Shutemov
