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[2003:d8:2f0a:7f00:fad7:3bc9:69d:31f]) by smtp.gmail.com with ESMTPSA id b20sm11829216wmj.7.2021.07.05.00.44.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 05 Jul 2021 00:44:31 -0700 (PDT) Subject: Re: [PATCH v1] mm: Enable suspend-only swap spaces To: Evan Green , Andrew Morton Cc: Alex Shi , Alistair Popple , Jens Axboe , Johannes Weiner , Joonsoo Kim , "Matthew Wilcox (Oracle)" , Miaohe Lin , Minchan Kim , Stephen Rothwell , Vlastimil Babka , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20210630100432.v1.1.I09866d90c6de14f21223a03e9e6a31f8a02ecbaf@changeid> From: David Hildenbrand Organization: Red Hat Message-ID: Date: Mon, 5 Jul 2021 09:44:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210630100432.v1.1.I09866d90c6de14f21223a03e9e6a31f8a02ecbaf@changeid> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30.06.21 19:07, Evan Green wrote: > Currently it's not possible to enable hibernation without also enabling > generic swap for a given swap area. These two use cases are not the > same. For example there may be users who want to enable hibernation, > but whose drives don't have the write endurance for generic swap > activities. > > Add a new SWAP_FLAG_NOSWAP that adds a swap region but refuses to allow > generic swapping to it. This region can still be wired up for use in > suspend-to-disk activities, but will never have regular pages swapped to > it. Just to confirm: things like /proc/meminfo won't show this "swap that's not actually swap" as free/total swap, correct? Maybe it's worth spelling the expected system behavior out here. -- Thanks, David / dhildenb