On 2024/1/3 09:53, Roman Gushchin wrote: > On Thu, Dec 28, 2023 at 06:27:14AM +0000, Haifeng Xu wrote: >> Actually, when using a boot time kernel option "cgroup.memory=nokmem", >> all lru items are inserted to list_lru_node. But for those users who >> invoke list_lru_init_memcg() to initialize list_lru, list_lru_memcg_aware() >> returns true. And this brings unneeded operations related to memcg. >> >> To make things more convenient, let's disable memcg_aware when >> cgroup.memory is set to "nokmem". > > I guess it's not only more convenient, but also should save a bit of memory. > But _probably_ not enough to justify messing up with stable backports. > Do you have any data on memory savings? Do you mean that it will remove the allocation of 'list_lru_memcg' in memcg_init_list_lru_one()? In fact, even without this patch, if we set cgroup.memory set to "nokmem", all memcg's kmemcg_id is -1, so memcg_list_lru_allocated() always returns true and we won't invoke memcg_init_list_lru_one(). > >> >> Signed-off-by: Haifeng Xu <haifeng.xu@xxxxxxxxxx> > > Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx> > > Thanks!
