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Date:   Thu, 25 Aug 2022 19:01:45 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Liu Shixin <liushixin2@huawei.com>
Cc:     Seth Jennings <sjenning@redhat.com>,
        Dan Streetman <ddstreet@ieee.org>,
        Vitaly Wool <vitaly.wool@konsulko.com>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -next 2/3] mm/zswap: delay the initializaton of zswap
 until the first enablement
Message-Id: <20220825190145.b0fc3267e16705866660f947@linux-foundation.org>
In-Reply-To: <20220825142037.3214152-3-liushixin2@huawei.com>
References: <20220825142037.3214152-1-liushixin2@huawei.com>
        <20220825142037.3214152-3-liushixin2@huawei.com>
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On Thu, 25 Aug 2022 22:20:36 +0800 Liu Shixin <liushixin2@huawei.com> wrote:

> In the initialization of zswap, about 18MB memory will be allocated for
> zswap_pool in my machine. Since not all users use zswap, the memory may be
> wasted. Save the memory for these users by delaying the initialization of
> zswap to first enablement.
> 
> ...
>
> +static int __init init_zswap(void)
> +{
> +	/* skip init if zswap is disabled when system startup */
> +	if (!zswap_enabled)
> +		return 0;
> +	return zswap_setup();
> +}
> +

I can't resist.

--- a/mm/zswap.c~mm-zswap-delay-the-initializaton-of-zswap-until-the-first-enablement-fix
+++ a/mm/zswap.c
@@ -1556,7 +1556,7 @@ cache_fail:
 	return -ENOMEM;
 }
 
-static int __init init_zswap(void)
+static int __init zswap_init(void)
 {
 	/* skip init if zswap is disabled when system startup */
 	if (!zswap_enabled)
@@ -1565,7 +1565,7 @@ static int __init init_zswap(void)
 }
 
 /* must be late so crypto has time to come up */
-late_initcall(init_zswap);
+late_initcall(zswap_init);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Seth Jennings <sjennings@variantweb.net>");

It's the usual way and makes things more consistent.