From: Andrew Morton <akpm@linux-foundation.org>
To: Evan Green <evgreen@chromium.org>
Cc: linux-api@vger.kernel.org, David Hildenbrand <david@redhat.com>,
Michal Hocko <mhocko@suse.com>, Pavel Machek <pavel@ucw.cz>,
Alex Shi <alexs@kernel.org>, Alistair Popple <apopple@nvidia.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Miaohe Lin <linmiaohe@huawei.com>,
Minchan Kim <minchan@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v3] mm: Enable suspend-only swap spaces
Date: Wed, 21 Jul 2021 15:09:26 -0700 [thread overview]
Message-ID: <20210721150926.ce56fb8b5fa733d9727bd37e@linux-foundation.org> (raw)
In-Reply-To: <20210721143946.v3.1.I09866d90c6de14f21223a03e9e6a31f8a02ecbaf@changeid>
On Wed, 21 Jul 2021 14:40:28 -0700 Evan Green <evgreen@chromium.org> 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. Swap and hibernate also have different security/integrity
> requirements, prompting folks to possibly set up something like block-level
> integrity for swap and image-level integrity for hibernate. Keeping swap
> and hibernate separate in these cases becomes not just a matter of
> preference, but correctness.
>
> 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. This flag will be passed in by utilities like swapon(8), usage would
> probably look something like: swapon -o noswap /dev/sda2.
Will patches to swapon and its manpage be prepared?
> Swap regions with SWAP_FLAG_NOSWAP set will not appear in /proc/meminfo
> under SwapTotal and SwapFree, since they are not usable as general swap.
>
next prev parent reply other threads:[~2021-07-21 22:09 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-21 21:40 [PATCH v3] mm: Enable suspend-only swap spaces Evan Green
2021-07-21 22:09 ` Andrew Morton [this message]
2021-07-22 17:16 ` Evan Green
2021-07-22 7:12 ` David Hildenbrand
2021-07-22 18:00 ` Evan Green
2021-07-23 6:58 ` David Hildenbrand
2021-07-23 17:42 ` Evan Green
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