Re: [PATCH 0/4] memcg: cleanup the memcg stats interfaces

[Qi Zheng <qi.zheng@linux.dev>]

Hi Shakeel,

On 11/11/25 7:20 AM, Shakeel Butt wrote:
> The memcg stats are safe against irq (and nmi) context and thus does not
> require disabling irqs. However for some stats which are also maintained
> at node level, it is using irq unsafe interface and thus requiring the
> users to still disables irqs or use interfaces which explicitly disables
> irqs. Let's move memcg code to use irq safe node level stats function
> which is already optimized for architectures with HAVE_CMPXCHG_LOCAL
> (all major ones), so there will not be any performance penalty for its
> usage.

Generally, places that call __mod_lruvec_state() also call
__mod_zone_page_state(), and it also has the corresponding optimized
version (mod_zone_page_state()). It seems necessary to clean that up
as well, so that those disabling-IRQs that are only used for updating
vmstat can be removed.

Thanks,
Qi

> 
> Shakeel Butt (4):
>    memcg: use mod_node_page_state to update stats
>    memcg: remove __mod_lruvec_kmem_state
>    memcg: remove __mod_lruvec_state
>    memcg: remove __lruvec_stat_mod_folio
> 
>   include/linux/memcontrol.h | 28 ++++------------------
>   include/linux/mm_inline.h  |  2 +-
>   include/linux/vmstat.h     | 48 ++------------------------------------
>   mm/filemap.c               | 20 ++++++++--------
>   mm/huge_memory.c           |  4 ++--
>   mm/khugepaged.c            |  8 +++----
>   mm/memcontrol.c            | 20 ++++++++--------
>   mm/migrate.c               | 20 ++++++++--------
>   mm/page-writeback.c        |  2 +-
>   mm/rmap.c                  |  4 ++--
>   mm/shmem.c                 |  6 ++---
>   mm/vmscan.c                |  4 ++--
>   mm/workingset.c            |  2 +-
>   13 files changed, 53 insertions(+), 115 deletions(-)
>