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Date:   Mon, 17 Jul 2023 17:07:46 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Vlastimil Babka <vbabka@suse.cz>,
        Andrew Morton <akpm@linux-foundation.org>,
        Yosry Ahmed <yosryahmed@google.com>,
        Christoph Hellwig <hch@infradead.org>,
        Nhat Pham <nphamcs@gmail.com>,
        Domenico Cerasuolo <cerasuolodomenico@gmail.com>,
        konrad.wilk@oracle.com, vitaly.wool@konsulko.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: kill frontswap
Message-ID: <ZLVnUhXeZ6ptNF2l@casper.infradead.org>
References: <20230714194610.828210-1-hannes@cmpxchg.org>
 <ZLIVleBYOm4HIGTZ@casper.infradead.org>
 <20230717141250.GA866068@cmpxchg.org>
 <901409ed-504b-9500-54d8-e42f832e07b0@suse.cz>
 <20230717160227.GA867137@cmpxchg.org>
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On Mon, Jul 17, 2023 at 12:02:27PM -0400, Johannes Weiner wrote:
> -	pr_info("Adding %uk swap on %s.  Priority:%d extents:%d across:%lluk %s%s%s%s%s\n",
> +	pr_info("Adding %uk swap on %s.  Priority:%d extents:%d across:%lluk %s%s%s%s\n",
>  		p->pages<<(PAGE_SHIFT-10), name->name, p->prio,
>  		nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10),
>  		(p->flags & SWP_SOLIDSTATE) ? "SS" : "",
>  		(p->flags & SWP_DISCARDABLE) ? "D" : "",
>  		(p->flags & SWP_AREA_DISCARD) ? "s" : "",
> -		(p->flags & SWP_PAGE_DISCARD) ? "c" : "",
> -		(frontswap_map) ? "FS" : "");
> +		(p->flags & SWP_PAGE_DISCARD) ? "c" : "");

Is it useful information (to the sysadmin) that zswap is enabled?  If so,
we might want to print a "Z" instead of a "FS" here (would need to
know whether enabling zswap succeeded ...)