On Wed, 21 Jul 2021 14:40:28 -0700 Evan Green <evgreen@xxxxxxxxxxxx> 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. >
