On Wed, 12 Feb 2025 04:28PM +0000, Matthew Wilcox wrote:
>On Wed, Feb 12, 2025 at 10:06:27AM +0800, Shengken Lin wrote:
>> The function of PageMemcgKmem(page) is the same as that of
>> folio_memcg_kmem(folio).
>> 
>> Since __memcg_kmem_uncharge_page already uses folio_memcg_kmem to check
>> if a folio has been uncharged, calling PageMemcgKmem(page) before
>> __memcg_kmem_uncharge_page is redundant.
>
>But it saves a function call.  NAK.
Hi Matthew Wilcox,
If it can save a function call, then adding PageMemcgKmem(page)
in include/linux/memcontrol.h would make the code more consistent.
If this is considered more reasonable, I can submit a new patch.
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1707,7 +1707,7 @@ static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp,
 
 static inline void memcg_kmem_uncharge_page(struct page *page, int order)
 {
-       if (memcg_kmem_online())
+       if (memcg_kmem_online() && PageMemcgKmem(page))
                __memcg_kmem_uncharge_page(page, order);
 }
--
Best regards,
Shengken Lin