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From: Qi Zheng In-Reply-To: <46bgg2vwqvmex7wtk2fkvf454tqgaychb7l4odnnrx7svci5ha@vy4b4ophm763> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Stat-Signature: uoqr8s9cfuxyow9yys5c6kwbsxiqgi4o X-Rspamd-Queue-Id: 4517980009 X-Rspamd-Server: rspam03 X-HE-Tag: 1772594655-570806 X-HE-Meta: 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 jjldbbqs zML5nwCV2MZd3bOZPiJ8651rYQquuERkSatRvn1DoW7b4zVoTr4SCtkmqQiYsN29QTOXsn0Rj+cqOUkoSknZDijIkahhGVNr4Q6e/x8MtjMT87D5wt2RlnPKyC0g7ZzyoPLqjadftLm4ncpjR9YnKqZu+IrrdF+Bv38DrQwxEdA5U0t0D8bpbJRqd+SqeTQaY9yx9stKaDoQF+gpSB3irbWNaHw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/3/26 10:56 PM, Yosry Ahmed wrote: > On Tue, Mar 03, 2026 at 11:08:56AM +0800, Qi Zheng wrote: >> Hi Yosry, > [..] >>> >>> 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]. > > I cannot apply the diff, seems a bit corrupted. > > But ideally, instead of a @reparent argument, we just have > __mod_memcg_lruvec_state() and __mod_memcg_state() do the work without > getting parent of dead memcgs, and then mod_memcg_lruvec_state() and > mod_memcg_state() just call them after get_non_dying_memcg_start(). > > What about this (untested), it should apply on top of 'mm: memcontrol: > eliminate the problem of dying memory cgroup for LRU folios' in mm-new, > so maybe it needs to be broken down across different patches: It looks feasible. I will apply and test it. If there are no problems, I will send the update patch. Thanks, Qi > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 753d76e96cc67..f0d55e1f9c49a 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -527,7 +527,7 @@ unsigned long lruvec_page_state_local(struct lruvec *lruvec, > } > > #ifdef CONFIG_MEMCG_V1 > -static void __mod_memcg_lruvec_state(struct lruvec *lruvec, > +static void __mod_memcg_lruvec_state(struct mem_cgroup_per_node *pn, > enum node_stat_item idx, int val); > > void reparent_memcg_lruvec_state_local(struct mem_cgroup *memcg, > @@ -536,16 +536,17 @@ void reparent_memcg_lruvec_state_local(struct mem_cgroup *memcg, > int i = memcg_stats_index(idx); > int nid; > > - if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) > - return; > - > for_each_node(nid) { > struct lruvec *child_lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); > struct lruvec *parent_lruvec = mem_cgroup_lruvec(parent, NODE_DATA(nid)); > unsigned long value = lruvec_page_state_local(child_lruvec, idx); > + struct mem_cgroup_per_node *child_pn, *parent_pn; > > - __mod_memcg_lruvec_state(child_lruvec, idx, -value); > - __mod_memcg_lruvec_state(parent_lruvec, idx, value); > + child_pn = container_of(child_lruvec, struct mem_cgroup_per_node, lruvec); > + parent_pn = container_of(parent_lruvec, struct mem_cgroup_per_node, lruvec); > + > + __mod_memcg_lruvec_state(child_pn, idx, -value); > + __mod_memcg_lruvec_state(parent_pn, idx, value); > } > } > #endif > @@ -831,39 +832,42 @@ 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) > { > int i = memcg_stats_index(idx); > int cpu; > > - if (mem_cgroup_disabled()) > - return; > - > if (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); > - > 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(); > - > 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) > +{ > + if (mem_cgroup_disabled()) > + return; > + > + memcg = get_non_dying_memcg_start(memcg); > + __mod_memcg_state(memcg, idx, val); > + get_non_dying_memcg_end(); > +} > + > #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) > @@ -882,35 +886,26 @@ 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) > +void reparent_memcg_state_local(struct mem_cgroup *memcg, > + struct mem_cgroup *parent, int idx) > { > 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); > + unsigned long value = memcg_page_state_local(memcg, idx); > > - put_cpu(); > + __mod_memcg_state(memcg, idx, -value); > + __mod_memcg_state(parent, idx, value); > } > +#endif > > -static void __mod_memcg_lruvec_state(struct lruvec *lruvec, > +static void __mod_memcg_lruvec_state(struct mem_cgroup_per_node *pn, > enum node_stat_item idx, int val) > { > - struct mem_cgroup_per_node *pn; > - struct mem_cgroup *memcg; > + struct mem_cgroup *memcg = pn->memcg; > int i = memcg_stats_index(idx); > int cpu; > > - pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); > - memcg = pn->memcg; > + if (WARN_ONCE(BAD_STAT_IDX(i), "%s: missing stat item %d\n", __func__, idx)) > + return; > > cpu = get_cpu(); > > @@ -927,20 +922,6 @@ static void __mod_memcg_lruvec_state(struct lruvec *lruvec, > put_cpu(); > } > > -void reparent_memcg_state_local(struct mem_cgroup *memcg, > - struct mem_cgroup *parent, int idx) > -{ > - int i = memcg_stats_index(idx); > - unsigned long value = memcg_page_state_local(memcg, idx); > - > - 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); > -} > -#endif > - > static void mod_memcg_lruvec_state(struct lruvec *lruvec, > enum node_stat_item idx, > int val) > @@ -948,32 +929,13 @@ static void mod_memcg_lruvec_state(struct lruvec *lruvec, > struct pglist_data *pgdat = lruvec_pgdat(lruvec); > struct mem_cgroup_per_node *pn; > struct mem_cgroup *memcg; > - int i = memcg_stats_index(idx); > - int cpu; > - > - if (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); > - memcg = pn->memcg; > - > - cpu = get_cpu(); > - > - memcg = get_non_dying_memcg_start(memcg); > + memcg = get_non_dying_memcg_start(pn->memcg); > pn = memcg->nodeinfo[pgdat->node_id]; > - > - /* 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); > - > + __mod_memcg_lruvec_state(pn, idx, val); > get_non_dying_memcg_end(); > > - trace_mod_memcg_lruvec_state(memcg, idx, val); > - > - put_cpu(); > } > > /