Re: Fixing memcg_slabinfo.py

[Roman Gushchin <roman.gushchin@linux.dev>]

Matthew Wilcox <willy@infradead.org> writes:

> Looks like nobody's used memcg_slabinfo.py in the last year when I broke
> it with 4ffca5a96678.  It should probably be fixed, but I'm not fluent
> in Python and don't use drgn myself, so have no way to verify the below
> is even syntactically correct, let alone works.

Hi Matthew!

The patch looks good to me (assuming a proper commit log). I gave it a
test on top of 6.14.9 (which is running my Fedora laptop currently) and
it worked fine.

Tested-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>

Thanks!

>
> diff --git a/tools/cgroup/memcg_slabinfo.py b/tools/cgroup/memcg_slabinfo.py
> index 270c28a0d098..bb3de16e3510 100644
> --- a/tools/cgroup/memcg_slabinfo.py
> +++ b/tools/cgroup/memcg_slabinfo.py
> @@ -146,11 +146,11 @@ def detect_kernel_config():
>  
>  
>  def for_each_slab(prog):
> -    PGSlab = ~prog.constant('PG_slab')
> +    PGTYslab = prog.constant('PGTY_slab')
>  
>      for page in for_each_page(prog):
>          try:
> -            if page.page_type.value_() == PGSlab:
> +            if (page.page_type.value_() >> 24) == PGTYslab:
>                  yield cast('struct slab *', page)
>          except FaultError:
>              pass