mm: memory: move mem_cgroup_charge() into alloc_anon_folio()
authorKefeng Wang <wangkefeng.wang@huawei.com>
Wed, 17 Jan 2024 10:39:54 +0000 (18:39 +0800)
committerAndrew Morton <akpm@linux-foundation.org>
Thu, 22 Feb 2024 18:24:38 +0000 (10:24 -0800)
commit085ff35e76368455c629b194bf3cb62dd82eadf6
treec8ff14e2851b765b0659ed2063e315d55c7a5a09
parent2444172cfde45a3d6e655f50c620727c76bab4a2
mm: memory: move mem_cgroup_charge() into alloc_anon_folio()

The GFP flags from vma_thp_gfp_mask() according to user configuration only
used for large folio allocation but not for memory cgroup charge, and
GFP_KERNEL is used for both order-0 and large order folio when memory
cgroup charge at present.  However, mem_cgroup_charge() uses the GFP flags
in a fairly sophisticated way.  In addition to checking
gfpflags_allow_blocking(), it pays attention to __GFP_NORETRY and
__GFP_RETRY_MAYFAIL to ensure that processes within this memcg do not
exceed their quotas.

So we'd better to move mem_cgroup_charge() into alloc_anon_folio(),

1) it will make us to allocate as much as possible large order folio,
   because we could try the next order if mem_cgroup_charge() fails,
   although the memcg's memory usage is close to its limits.

2) using same GFP flags for allocation and charge is to be consistent
   with PMD THP firstly, in addition, according to GFP flag returned from
   vma_thp_gfp_mask(), GFP_TRANSHUGE_LIGHT could make us skip direct
   reclaim, _GFP_NORETRY will make us skip mem_cgroup_oom() and won't
   trigger memory cgroup oom from large order(order <= COSTLY_ORDER) folio
   charging.

Link: https://lkml.kernel.org/r/20240122011612.501029-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240117103954.2756050-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/memory.c