linux-kernel - Re: [PATCH v8 3/8] mm: zswap: Rename zswap_pool_get() to zswap_pool

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Message-ID: <CAJD7tkZKSX3bLjhtQ+uEB+mrpJ+Q_HysvnQ88hWuf3fqvFx=Zg@mail.gmail.com>
Date: Fri, 27 Sep 2024 19:29:07 -0700
From: Yosry Ahmed <yosryahmed@...gle.com>
To: Kanchana P Sridhar <kanchana.p.sridhar@...el.com>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org, hannes@...xchg.org, 
	nphamcs@...il.com, chengming.zhou@...ux.dev, usamaarif642@...il.com, 
	shakeel.butt@...ux.dev, ryan.roberts@....com, ying.huang@...el.com, 
	21cnbao@...il.com, akpm@...ux-foundation.org, nanhai.zou@...el.com, 
	wajdi.k.feghali@...el.com, vinodh.gopal@...el.com
Subject: Re: [PATCH v8 3/8] mm: zswap: Rename zswap_pool_get() to zswap_pool_tryget().

On Fri, Sep 27, 2024 at 7:16 PM Kanchana P Sridhar
<kanchana.p.sridhar@...el.com> wrote:
>
> Modify the name of the existing zswap_pool_get() to zswap_pool_tryget()
> to be representative of the call it makes to percpu_ref_tryget().
> A subsequent patch will introduce a new zswap_pool_get() that calls
> percpu_ref_get().
>
> The intent behind this change is for higher level zswap API such as
> zswap_store() to call zswap_pool_tryget() to check upfront if the pool's
> refcount is "0" (which means it could be getting destroyed) and to handle
> this as an error condition. zswap_store() would proceed only if
> zswap_pool_tryget() returns success, and any additional pool refcounts that
> need to be obtained for compressing sub-pages in a large folio could simply
> call zswap_pool_get().
>
> Signed-off-by: Kanchana P Sridhar <kanchana.p.sridhar@...el.com>

Acked-by: Yosry Ahmed <yosryahmed@...gle.com>

> ---
>  mm/zswap.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index fd7a8c14457a..0f281e50a034 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -403,7 +403,7 @@ static void __zswap_pool_empty(struct percpu_ref *ref)
>         spin_unlock_bh(&zswap_pools_lock);
>  }
>
> -static int __must_check zswap_pool_get(struct zswap_pool *pool)
> +static int __must_check zswap_pool_tryget(struct zswap_pool *pool)
>  {
>         if (!pool)
>                 return 0;
> @@ -441,7 +441,7 @@ static struct zswap_pool *zswap_pool_current_get(void)
>         rcu_read_lock();
>
>         pool = __zswap_pool_current();
> -       if (!zswap_pool_get(pool))
> +       if (!zswap_pool_tryget(pool))
>                 pool = NULL;
>
>         rcu_read_unlock();
> @@ -462,7 +462,7 @@ static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
>                 if (strcmp(zpool_get_type(pool->zpool), type))
>                         continue;
>                 /* if we can't get it, it's about to be destroyed */
> -               if (!zswap_pool_get(pool))
> +               if (!zswap_pool_tryget(pool))
>                         continue;
>                 return pool;
>         }
> --
> 2.27.0
>