From: Qi Zheng <qi.zheng@linux.dev>
To: Yosry Ahmed <yosry@kernel.org>
Cc: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com,
roman.gushchin@linux.dev, shakeel.butt@linux.dev,
muchun.song@linux.dev, david@kernel.org,
lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com,
yosry.ahmed@linux.dev, imran.f.khan@oracle.com,
kamalesh.babulal@oracle.com, axelrasmussen@google.com,
yuanchu@google.com, weixugc@google.com,
chenridong@huaweicloud.com, mkoutny@suse.com,
akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com,
apais@linux.microsoft.com, lance.yang@linux.dev, bhe@redhat.com,
usamaarif642@gmail.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
Qi Zheng <zhengqi.arch@bytedance.com>
Subject: Re: [PATCH v5 update 29/32] mm: memcontrol: prepare for reparenting non-hierarchical stats
Date: Tue, 3 Mar 2026 11:08:56 +0800 [thread overview]
Message-ID: <de1476aa-20a3-420e-9cd7-9238efd3c85f@linux.dev> (raw)
In-Reply-To: <CAO9r8zNYFvNnz_oTu10kPBYL6=1ZewKUMRYcMmcMdSqbro_miA@mail.gmail.com>
Hi Yosry,
On 3/2/26 11:53 PM, Yosry Ahmed wrote:
> [..]
>> @@ -763,6 +851,64 @@ unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
>> #endif
>> return x;
>> }
>> +
>> +static void __mod_memcg_state(struct mem_cgroup *memcg,
>> + enum memcg_stat_item idx, int val)
>> +{
>> + int i = memcg_stats_index(idx);
>> + int cpu;
>> +
>> + if (mem_cgroup_disabled())
>> + return;
>> +
>> + cpu = get_cpu();
>> +
>> + this_cpu_add(memcg->vmstats_percpu->state[i], val);
>> + val = memcg_state_val_in_pages(idx, val);
>> + memcg_rstat_updated(memcg, val, cpu);
>> + trace_mod_memcg_state(memcg, idx, val);
>> +
>> + put_cpu();
>> +}
>> +
>> +static void __mod_memcg_lruvec_state(struct lruvec *lruvec,
>> + enum node_stat_item idx, int val)
>> +{
>> + struct mem_cgroup_per_node *pn;
>> + struct mem_cgroup *memcg;
>> + int i = memcg_stats_index(idx);
>> + int cpu;
>> +
>> + pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
>> + memcg = pn->memcg;
>> +
>> + cpu = get_cpu();
>> +
>> + /* Update memcg */
>> + this_cpu_add(memcg->vmstats_percpu->state[i], val);
>> +
>> + /* Update lruvec */
>> + this_cpu_add(pn->lruvec_stats_percpu->state[i], val);
>> +
>> + val = memcg_state_val_in_pages(idx, val);
>> + memcg_rstat_updated(memcg, val, cpu);
>> + trace_mod_memcg_lruvec_state(memcg, idx, val);
>> +
>> + put_cpu();
>> +}
>
> I don't think we should end up with two copies of
> __mod_memcg_state/mod_memcg_state() and
> __mod_memcg_lruvec_state/mod_memcg_lruvec_state(). I meant to refactor
> mod_memcg_state() to call __mod_memcg_state(), where the latter does
> not call get_non_dying_memcg_{start/end}(). Same for
> mod_memcg_lruvec_state().
Okay, like the following? But this would require modifications to
[PATCH v5 31/32]. If there are no problems, I will send the updated
patch to [PATCH v5 29/32] and [PATCH v5 31/32].
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e927530156fee..3d9e2cfad5b12 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -528,7 +528,8 @@ unsigned long lruvec_page_state_local(struct lruvec
*lruvec,
#ifdef CONFIG_MEMCG_V1
static void __mod_memcg_lruvec_state(struct lruvec *lruvec,
- enum node_stat_item idx, int val);
+ enum node_stat_item idx, int val,
+ bool reparent);
void reparent_memcg_lruvec_state_local(struct mem_cgroup *memcg,
struct mem_cgroup *parent, int idx)
@@ -544,8 +545,8 @@ void reparent_memcg_lruvec_state_local(struct
mem_cgroup *memcg,
struct lruvec *parent_lruvec =
mem_cgroup_lruvec(parent, NODE_DATA(nid));
unsigned long value =
lruvec_page_state_local(child_lruvec, idx);
- __mod_memcg_lruvec_state(child_lruvec, idx, -value);
- __mod_memcg_lruvec_state(parent_lruvec, idx, value);
+ __mod_memcg_lruvec_state(child_lruvec, idx, -value, true);
+ __mod_memcg_lruvec_state(parent_lruvec, idx, value, true);
}
}
#endif
@@ -831,14 +832,9 @@ static inline void get_non_dying_memcg_end(void)
}
#endif
-/**
- * mod_memcg_state - update cgroup memory statistics
- * @memcg: the memory cgroup
- * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
- * @val: delta to add to the counter, can be negative
- */
-void mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
- int val)
+static void __mod_memcg_state(struct mem_cgroup *memcg,
+ enum memcg_stat_item idx, int val,
+ bool reparent)
{
int i = memcg_stats_index(idx);
int cpu;
@@ -846,24 +842,38 @@ void mod_memcg_state(struct mem_cgroup *memcg,
enum memcg_stat_item idx,
if (mem_cgroup_disabled())
return;
- if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n",
__func__, idx))
+ if (!reparent && WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat
item %d\n", __func__, idx))
return;
cpu = get_cpu();
- memcg = get_non_dying_memcg_start(memcg);
+ if (!reparent)
+ memcg = get_non_dying_memcg_start(memcg);
this_cpu_add(memcg->vmstats_percpu->state[i], val);
val = memcg_state_val_in_pages(idx, val);
memcg_rstat_updated(memcg, val, cpu);
- get_non_dying_memcg_end();
+ if (!reparent)
+ get_non_dying_memcg_end();
trace_mod_memcg_state(memcg, idx, val);
put_cpu();
}
+/**
+ * mod_memcg_state - update cgroup memory statistics
+ * @memcg: the memory cgroup
+ * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
+ * @val: delta to add to the counter, can be negative
+ */
+void mod_memcg_state(struct mem_cgroup *memcg, enum memcg_stat_item idx,
+ int val)
+{
+ __mod_memcg_state(memcg, idx, val, false);
+}
+
#ifdef CONFIG_MEMCG_V1
/* idx can be of type enum memcg_stat_item or node_stat_item. */
unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx)
@@ -882,51 +892,6 @@ unsigned long memcg_page_state_local(struct
mem_cgroup *memcg, int idx)
return x;
}
-static void __mod_memcg_state(struct mem_cgroup *memcg,
- enum memcg_stat_item idx, int val)
-{
- int i = memcg_stats_index(idx);
- int cpu;
-
- if (mem_cgroup_disabled())
- return;
-
- cpu = get_cpu();
-
- this_cpu_add(memcg->vmstats_percpu->state[i], val);
- val = memcg_state_val_in_pages(idx, val);
- memcg_rstat_updated(memcg, val, cpu);
- trace_mod_memcg_state(memcg, idx, val);
-
- put_cpu();
-}
-
-static void __mod_memcg_lruvec_state(struct lruvec *lruvec,
- enum node_stat_item idx, int val)
-{
- struct mem_cgroup_per_node *pn;
- struct mem_cgroup *memcg;
- int i = memcg_stats_index(idx);
- int cpu;
-
- pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
- memcg = pn->memcg;
-
- cpu = get_cpu();
-
- /* Update memcg */
- this_cpu_add(memcg->vmstats_percpu->state[i], val);
-
- /* Update lruvec */
- this_cpu_add(pn->lruvec_stats_percpu->state[i], val);
-
- val = memcg_state_val_in_pages(idx, val);
- memcg_rstat_updated(memcg, val, cpu);
- trace_mod_memcg_lruvec_state(memcg, idx, val);
-
- put_cpu();
-}
-
void reparent_memcg_state_local(struct mem_cgroup *memcg,
struct mem_cgroup *parent, int idx)
{
@@ -936,14 +901,14 @@ void reparent_memcg_state_local(struct mem_cgroup
*memcg,
if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n",
__func__, idx))
return;
- __mod_memcg_state(memcg, idx, -value);
- __mod_memcg_state(parent, idx, value);
+ __mod_memcg_state(memcg, idx, -value, true);
+ __mod_memcg_state(parent, idx, value, true);
}
#endif
-static void mod_memcg_lruvec_state(struct lruvec *lruvec,
- enum node_stat_item idx,
- int val)
+static void __mod_memcg_lruvec_state(struct lruvec *lruvec,
+ enum node_stat_item idx, int val,
+ bool reparent)
{
struct pglist_data *pgdat = lruvec_pgdat(lruvec);
struct mem_cgroup_per_node *pn;
@@ -951,7 +916,7 @@ static void mod_memcg_lruvec_state(struct lruvec
*lruvec,
int i = memcg_stats_index(idx);
int cpu;
- if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n",
__func__, idx))
+ if (!reparent && WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat
item %d\n", __func__, idx))
return;
pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
@@ -959,8 +924,10 @@ static void mod_memcg_lruvec_state(struct lruvec
*lruvec,
cpu = get_cpu();
- memcg = get_non_dying_memcg_start(memcg);
- pn = memcg->nodeinfo[pgdat->node_id];
+ if (!reparent) {
+ memcg = get_non_dying_memcg_start(memcg);
+ pn = memcg->nodeinfo[pgdat->node_id];
+ }
/* Update memcg */
this_cpu_add(memcg->vmstats_percpu->state[i], val);
@@ -969,13 +936,21 @@ static void mod_memcg_lruvec_state(struct lruvec
*lruvec,
val = memcg_state_val_in_pages(idx, val);
memcg_rstat_updated(memcg, val, cpu);
- get_non_dying_memcg_end();
+ if (!reparent)
+ get_non_dying_memcg_end();
trace_mod_memcg_lruvec_state(memcg, idx, val);
put_cpu();
}
+static void mod_memcg_lruvec_state(struct lruvec *lruvec,
+ enum node_stat_item idx,
+ int val)
+{
+ __mod_memcg_lruvec_state(lruvec, idx, val, false);
+}
+
/**
* mod_lruvec_state - update lruvec memory statistics
* @lruvec: the lruvec
>
next prev parent reply other threads:[~2026-03-03 3:09 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-25 7:48 [PATCH v5 00/32] Eliminate Dying Memory Cgroup Qi Zheng
2026-02-25 7:48 ` [PATCH v5 01/32] mm: memcontrol: remove dead code of checking parent memory cgroup Qi Zheng
2026-02-25 7:48 ` [PATCH v5 02/32] mm: workingset: use folio_lruvec() in workingset_refault() Qi Zheng
2026-02-25 7:48 ` [PATCH v5 03/32] mm: rename unlock_page_lruvec_irq and its variants Qi Zheng
2026-02-25 7:48 ` [PATCH v5 04/32] mm: vmscan: prepare for the refactoring the move_folios_to_lru() Qi Zheng
2026-02-25 7:48 ` [PATCH v5 05/32] mm: vmscan: refactor move_folios_to_lru() Qi Zheng
2026-02-25 7:48 ` [PATCH v5 06/32] mm: memcontrol: allocate object cgroup for non-kmem case Qi Zheng
2026-02-25 7:48 ` [PATCH v5 07/32] mm: memcontrol: return root object cgroup for root memory cgroup Qi Zheng
2026-02-25 7:48 ` [PATCH v5 08/32] mm: memcontrol: prevent memory cgroup release in get_mem_cgroup_from_folio() Qi Zheng
2026-02-25 7:48 ` [PATCH v5 09/32] buffer: prevent memory cgroup release in folio_alloc_buffers() Qi Zheng
2026-02-25 7:48 ` [PATCH v5 10/32] writeback: prevent memory cgroup release in writeback module Qi Zheng
2026-02-25 7:48 ` [PATCH v5 11/32] mm: memcontrol: prevent memory cgroup release in count_memcg_folio_events() Qi Zheng
2026-02-25 7:48 ` [PATCH v5 12/32] mm: page_io: prevent memory cgroup release in page_io module Qi Zheng
2026-02-25 7:52 ` [PATCH v5 13/32] mm: migrate: prevent memory cgroup release in folio_migrate_mapping() Qi Zheng
2026-02-25 7:52 ` [PATCH v5 14/32] mm: mglru: prevent memory cgroup release in mglru Qi Zheng
2026-02-25 7:52 ` [PATCH v5 15/32] mm: memcontrol: prevent memory cgroup release in mem_cgroup_swap_full() Qi Zheng
2026-02-25 7:52 ` [PATCH v5 16/32] mm: workingset: prevent memory cgroup release in lru_gen_eviction() Qi Zheng
2026-02-25 7:53 ` [PATCH v5 17/32] mm: thp: prevent memory cgroup release in folio_split_queue_lock{_irqsave}() Qi Zheng
2026-02-25 7:53 ` [PATCH v5 18/32] mm: zswap: prevent memory cgroup release in zswap_compress() Qi Zheng
2026-02-25 7:53 ` [PATCH v5 19/32] mm: workingset: prevent lruvec release in workingset_refault() Qi Zheng
2026-02-25 7:53 ` [PATCH v5 20/32] mm: zswap: prevent lruvec release in zswap_folio_swapin() Qi Zheng
2026-02-25 7:53 ` [PATCH v5 21/32] mm: swap: prevent lruvec release in lru_gen_clear_refs() Qi Zheng
2026-02-25 7:53 ` [PATCH v5 22/32] mm: workingset: prevent lruvec release in workingset_activation() Qi Zheng
2026-02-25 7:53 ` [PATCH v5 23/32] mm: do not open-code lruvec lock Qi Zheng
2026-02-25 7:53 ` [PATCH v5 24/32] mm: memcontrol: prepare for reparenting LRU pages for " Qi Zheng
2026-02-25 7:53 ` [PATCH v5 25/32] mm: vmscan: prepare for reparenting traditional LRU folios Qi Zheng
2026-02-25 7:53 ` [PATCH v5 26/32] mm: vmscan: prepare for reparenting MGLRU folios Qi Zheng
2026-02-25 7:53 ` [PATCH v5 27/32] mm: memcontrol: refactor memcg_reparent_objcgs() Qi Zheng
2026-02-25 7:53 ` [PATCH v5 28/32] mm: workingset: use lruvec_lru_size() to get the number of lru pages Qi Zheng
2026-02-25 7:53 ` [PATCH v5 29/32] mm: memcontrol: prepare for reparenting non-hierarchical stats Qi Zheng
2026-02-25 14:58 ` Yosry Ahmed
2026-02-26 0:25 ` Shakeel Butt
2026-02-26 6:42 ` Qi Zheng
2026-02-26 15:16 ` Yosry Ahmed
2026-02-26 17:02 ` Shakeel Butt
2026-02-26 17:13 ` Yosry Ahmed
2026-02-27 3:11 ` Qi Zheng
2026-02-27 6:05 ` Qi Zheng
2026-02-27 18:18 ` Yosry Ahmed
2026-02-28 3:40 ` Qi Zheng
2026-02-26 6:41 ` Qi Zheng
2026-02-26 1:41 ` Shakeel Butt
2026-02-26 6:45 ` Qi Zheng
2026-02-28 7:25 ` [PATCH v5 update " Qi Zheng
2026-02-28 19:08 ` Andrew Morton
2026-03-02 2:30 ` Qi Zheng
2026-03-02 15:53 ` Yosry Ahmed
2026-03-03 3:08 ` Qi Zheng [this message]
2026-02-25 7:53 ` [PATCH v5 30/32] mm: memcontrol: convert objcg to be per-memcg per-node type Qi Zheng
2026-02-25 9:44 ` [PATCH v5 update " Qi Zheng
2026-02-26 2:27 ` Shakeel Butt
2026-02-26 6:47 ` Qi Zheng
2026-02-26 20:05 ` Shakeel Butt
2026-02-27 6:34 ` Qi Zheng
2026-02-25 7:53 ` [PATCH v5 31/32] mm: memcontrol: eliminate the problem of dying memory cgroup for LRU folios Qi Zheng
2026-02-26 2:40 ` Shakeel Butt
2026-02-25 7:53 ` [PATCH v5 32/32] mm: lru: add VM_WARN_ON_ONCE_FOLIO to lru maintenance helpers Qi Zheng
2026-02-25 21:57 ` [PATCH v5 00/32] Eliminate Dying Memory Cgroup Andrew Morton
2026-02-27 0:24 ` SeongJae Park
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