Re: [PATCH v3 1/7] mm/lru: add per lruvec lock for memcg

[Shakeel Butt]

On Fri, Nov 15, 2019 at 7:15 PM Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx> wrote:
>
> Currently memcg still use per node pgdat->lru_lock to guard its lruvec.
> That causes some lru_lock contention in a high container density system.
>
> If we can use per lruvec lock, that could relief much of the lru_lock
> contention.
>
> The later patches will replace the pgdat->lru_lock with lruvec->lru_lock
> and show the performance benefit by benchmarks.

Merge this patch with actual usage. No need to have a separate patch.

>
> Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Arun KS <arunks@xxxxxxxxxxxxxx>
> Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: cgroups@xxxxxxxxxxxxxxx
> Cc: linux-mm@xxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> ---
>  include/linux/mmzone.h | 2 ++
>  mm/mmzone.c            | 1 +
>  2 files changed, 3 insertions(+)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 07b784ffbb14..a13b8a602ee5 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -267,6 +267,8 @@ struct lruvec {
>         unsigned long                   refaults;
>         /* Various lruvec state flags (enum lruvec_flags) */
>         unsigned long                   flags;
> +       /* per lruvec lru_lock for memcg */
> +       spinlock_t                      lru_lock;
>  #ifdef CONFIG_MEMCG
>         struct pglist_data *pgdat;
>  #endif
> diff --git a/mm/mmzone.c b/mm/mmzone.c
> index 4686fdc23bb9..3750a90ed4a0 100644
> --- a/mm/mmzone.c
> +++ b/mm/mmzone.c
> @@ -91,6 +91,7 @@ void lruvec_init(struct lruvec *lruvec)
>         enum lru_list lru;
>
>         memset(lruvec, 0, sizeof(struct lruvec));
> +       spin_lock_init(&lruvec->lru_lock);
>
>         for_each_lru(lru)
>                 INIT_LIST_HEAD(&lruvec->lists[lru]);
> --
> 1.8.3.1
>