Re: [PATCH 1/2] mm/zswap: global lru and shrinker shared by all zswap_pools

From: Yosry Ahmed <yosryahmed@google.com>
To: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	 Nhat Pham <nphamcs@gmail.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] mm/zswap: global lru and shrinker shared by all zswap_pools
Date: Tue, 13 Feb 2024 17:43:35 +0000	[thread overview]
Message-ID: <ZcuqR7KeBPuarevU@google.com> (raw)
In-Reply-To: <e094857d-41c8-4064-8475-a5a43e315f6d@bytedance.com>

> >> @@ -353,30 +353,16 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
> >>  	if (ret)
> >>  		goto error;
> >>  
> >> -	zswap_alloc_shrinker(pool);
> >> -	if (!pool->shrinker)
> >> -		goto error;
> >> -
> >> -	pr_debug("using %s compressor\n", pool->tfm_name);
> >> -
> > 
> > Why are we removing this debug print?

This pr_debug() was introduced when dynamic zswap pools were introduced,
and it was supposed to be printed right after the compressor is
initialized. IOW, it is supposed to be after the call to
cpuhp_state_add_instance() succeeds. The call to zswap_alloc_shrinker()
was mistakenly added above that pr_debug() call.

Anyway, I just realized you are now removing all failure cases between
than pr_debug() and the zswap_pool_debug() below, so there is no need to
keep both. You are right.

I am wondering if these debug prints are useful at all now, but that's a
question for another day :)