Re: [PATCH v5 09/12] zsmalloc: separate free_zspage from putback_zspage

Sergey Senozhatsky
2016-05-16T03:15:38Z

On (05/09/16 11:20), Minchan Kim wrote:
> Currently, putback_zspage does free zspage under class->lock
> if fullness become ZS_EMPTY but it makes trouble to implement
> locking scheme for new zspage migration.
> So, this patch is to separate free_zspage from putback_zspage
> and free zspage out of class->lock which is preparation for
> zspage migration.
>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Signed-off-by: Minchan Kim <minchan@kernel.org>

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

-ss

> ---
> mm/zsmalloc.c | 27 +++++++++++----------------
> 1 file changed, 11 insertions(+), 16 deletions(-)
>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 162a598a417a..5ccd83732a14 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -1685,14 +1685,12 @@ static struct zspage *isolate_zspage(struct size_class *class, bool source)
>
> /*
> * putback_zspage - add @zspage into right class's fullness list
> - * @pool: target pool
> * @class: destination class
> * @zspage: target page
> *
> * Return @zspage's fullness_group
> */
> -static enum fullness_group putback_zspage(struct zs_pool *pool,
> - struct size_class *class,
> +static enum fullness_group putback_zspage(struct size_class *class,
> struct zspage *zspage)
> {
> enum fullness_group fullness;
> @@ -1701,15 +1699,6 @@ static enum fullness_group putback_zspage(struct zs_pool *pool,
> insert_zspage(class, zspage, fullness);
> set_zspage_mapping(zspage, class->index, fullness);
>
> - if (fullness == ZS_EMPTY) {
> - zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
> - class->size, class->pages_per_zspage));
> - atomic_long_sub(class->pages_per_zspage,
> - &pool->pages_allocated);
> -
> - free_zspage(pool, zspage);
> - }
> -
> return fullness;
> }
>
> @@ -1755,23 +1744,29 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class)
> if (!migrate_zspage(pool, class, &cc))
> break;
>
> - putback_zspage(pool, class, dst_zspage);
> + putback_zspage(class, dst_zspage);
> }
>
> /* Stop if we couldn't find slot */
> if (dst_zspage == NULL)
> break;
>
> - putback_zspage(pool, class, dst_zspage);
> - if (putback_zspage(pool, class, src_zspage) == ZS_EMPTY)
> + putback_zspage(class, dst_zspage);
> + if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
> + zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
> + class->size, class->pages_per_zspage));
> + atomic_long_sub(class->pages_per_zspage,
> + &pool->pages_allocated);
> + free_zspage(pool, src_zspage);
> pool->stats.pages_compacted += class->pages_per_zspage;
> + }
> spin_unlock(&class->lock);
> cond_resched();
> spin_lock(&class->lock);
> }
>
> if (src_zspage)
> - putback_zspage(pool, class, src_zspage);
> + putback_zspage(class, src_zspage);
>
> spin_unlock(&class->lock);
> }
> --
> 1.9.1
>
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