RE: [PATCH v8 3/8] mm: zswap: Rename zswap_pool_get() to zswap_pool_tryget().

["Sridhar, Kanchana P" <kanchana.p.sridhar@intel.com>]

> -----Original Message-----
> From: Chengming Zhou <chengming.zhou@linux.dev>
> Sent: Friday, September 27, 2024 10:44 PM
> To: Sridhar, Kanchana P <kanchana.p.sridhar@intel.com>; linux-
> kernel@vger.kernel.org; linux-mm@kvack.org; hannes@cmpxchg.org;
> yosryahmed@google.com; nphamcs@gmail.com; usamaarif642@gmail.com;
> shakeel.butt@linux.dev; ryan.roberts@arm.com; Huang, Ying
> <ying.huang@intel.com>; 21cnbao@gmail.com; akpm@linux-foundation.org
> Cc: Zou, Nanhai <nanhai.zou@intel.com>; Feghali, Wajdi K
> <wajdi.k.feghali@intel.com>; Gopal, Vinodh <vinodh.gopal@intel.com>
> Subject: Re: [PATCH v8 3/8] mm: zswap: Rename zswap_pool_get() to
> zswap_pool_tryget().
> 
> On 2024/9/28 10:16, Kanchana P Sridhar 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@intel.com>
> 
> Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>

Thanks Chengming!

Thanks,
Kanchana

> 
> > ---
> >   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;
> >   	}