Re: [PATCH 11/11] mm: enlarge the "int nr_pages" parameter of update_lru_size()

Alex Shi
2020-12-08T09:16:05Z

Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>

在 2020/12/8 上午6:09, Yu Zhao 写道:
> update_lru_sizes() defines an unsigned long argument and passes it as
> nr_pages to update_lru_size(). Though this isn't causing any overflows
> I'm aware of, it's a bad idea to go through the demotion given that we
> have recently stumbled on a related type promotion problem fixed by
> commit 2da9f6305f30 ("mm/vmscan: fix NR_ISOLATED_FILE corruption on 64-bit")
>
> Note that the underlying counters are already in long. This is another
> reason we shouldn't have the demotion.
>
> This patch enlarges all relevant parameters on the path to the final
> underlying counters:
> update_lru_size(int -> long)
> if memcg:
> __mod_lruvec_state(int -> long)
> if smp:
> __mod_node_page_state(long)
> else:
> __mod_node_page_state(int -> long)
> __mod_memcg_lruvec_state(int -> long)
> __mod_memcg_state(int -> long)
> else:
> __mod_lruvec_state(int -> long)
> if smp:
> __mod_node_page_state(long)
> else:
> __mod_node_page_state(int -> long)
>
> __mod_zone_page_state(long)
>
> if memcg:
> mem_cgroup_update_lru_size(int -> long)
>
> Note that __mod_node_page_state() for the smp case and
> __mod_zone_page_state() already use long. So this change also fixes
> the inconsistency.
>
> Signed-off-by: Yu Zhao <yuzhao@google.com>
> ---
> include/linux/memcontrol.h | 10 +++++-----
> include/linux/mm_inline.h | 2 +-
> include/linux/vmstat.h | 6 +++---
> mm/memcontrol.c | 10 +++++-----
> 4 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 3febf64d1b80..1454201abb8d 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -810,7 +810,7 @@ static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
> int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
>
> void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
> - int zid, int nr_pages);
> + int zid, long nr_pages);
>
> static inline
> unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
> @@ -896,7 +896,7 @@ static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
> return x;
> }
>
> -void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);
> +void __mod_memcg_state(struct mem_cgroup *memcg, int idx, long val);
>
> /* idx can be of type enum memcg_stat_item or node_stat_item */
> static inline void mod_memcg_state(struct mem_cgroup *memcg,
> @@ -948,7 +948,7 @@ static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
> }
>
> void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
> - int val);
> + long val);
> void __mod_lruvec_kmem_state(void *p, enum node_stat_item idx, int val);
>
> static inline void mod_lruvec_kmem_state(void *p, enum node_stat_item idx,
> @@ -1346,7 +1346,7 @@ static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
>
> static inline void __mod_memcg_state(struct mem_cgroup *memcg,
> int idx,
> - int nr)
> + long nr)
> {
> }
>
> @@ -1369,7 +1369,7 @@ static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
> }
>
> static inline void __mod_memcg_lruvec_state(struct lruvec *lruvec,
> - enum node_stat_item idx, int val)
> + enum node_stat_item idx, long val)
> {
> }
>
> diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
> index 355ea1ee32bd..18e85071b44a 100644
> --- a/include/linux/mm_inline.h
> +++ b/include/linux/mm_inline.h
> @@ -26,7 +26,7 @@ static inline int page_is_file_lru(struct page *page)
>
> static __always_inline void update_lru_size(struct lruvec *lruvec,
> enum lru_list lru, enum zone_type zid,
> - int nr_pages)
> + long nr_pages)
> {
> struct pglist_data *pgdat = lruvec_pgdat(lruvec);
>
> diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
> index 773135fc6e19..230922179ba0 100644
> --- a/include/linux/vmstat.h
> +++ b/include/linux/vmstat.h
> @@ -310,7 +310,7 @@ static inline void __mod_zone_page_state(struct zone *zone,
> }
>
> static inline void __mod_node_page_state(struct pglist_data *pgdat,
> - enum node_stat_item item, int delta)
> + enum node_stat_item item, long delta)
> {
> if (vmstat_item_in_bytes(item)) {
> VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
> @@ -453,7 +453,7 @@ static inline const char *vm_event_name(enum vm_event_item item)
> #ifdef CONFIG_MEMCG
>
> void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
> - int val);
> + long val);
>
> static inline void mod_lruvec_state(struct lruvec *lruvec,
> enum node_stat_item idx, int val)
> @@ -481,7 +481,7 @@ static inline void mod_lruvec_page_state(struct page *page,
> #else
>
> static inline void __mod_lruvec_state(struct lruvec *lruvec,
> - enum node_stat_item idx, int val)
> + enum node_stat_item idx, long val)
> {
> __mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
> }
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index de17f02d27ad..c3fe5880c42d 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -758,7 +758,7 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
> * @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, int idx, int val)
> +void __mod_memcg_state(struct mem_cgroup *memcg, int idx, long val)
> {
> long x, threshold = MEMCG_CHARGE_BATCH;
>
> @@ -796,7 +796,7 @@ parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid)
> }
>
> void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
> - int val)
> + long val)
> {
> struct mem_cgroup_per_node *pn;
> struct mem_cgroup *memcg;
> @@ -837,7 +837,7 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
> * change of state at this level: per-node, per-cgroup, per-lruvec.
> */
> void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
> - int val)
> + long val)
> {
> /* Update node */
> __mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
> @@ -1407,7 +1407,7 @@ struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
> * so as to allow it to check that lru_size 0 is consistent with list_empty).
> */
> void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
> - int zid, int nr_pages)
> + int zid, long nr_pages)
> {
> struct mem_cgroup_per_node *mz;
> unsigned long *lru_size;
> @@ -1424,7 +1424,7 @@ void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
>
> size = *lru_size;
> if (WARN_ONCE(size < 0,
> - "%s(%p, %d, %d): lru_size %ld\n",
> + "%s(%p, %d, %ld): lru_size %ld\n",
> __func__, lruvec, lru, nr_pages, size)) {
> VM_BUG_ON(1);
> *lru_size = 0;
>