Messages in this thread | | | Date | Sat, 24 Apr 2010 21:27:46 +0300 | From | Avi Kivity <> | Subject | Re: Frontswap [PATCH 0/4] (was Transcendent Memory): overview |
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On 04/24/2010 04:49 AM, Nitin Gupta wrote: > >> I see. So why not implement this as an ordinary swap device, with a >> higher priority than the disk device? this way we reuse an API and keep >> things asynchronous, instead of introducing a special purpose API. >> >> > ramzswap is exactly this: an ordinary swap device which stores every page > in (compressed) memory and its enabled as highest priority swap. Currently, > it stores these compressed chunks in guest memory itself but it is not very > difficult to send these chunks out to host/hypervisor using virtio. > > However, it suffers from unnecessary block I/O layer overhead and requires > weird hooks in swap code, say to get notification when a swap slot is freed. >
Isn't that TRIM?
> OTOH frontswap approach gets rid of any such artifacts and overheads. > (ramzswap: http://code.google.com/p/compcache/) >
Maybe we should optimize these overheads instead. Swap used to always be to slow devices, but swap-to-flash has the potential to make swap act like an extension of RAM.
-- Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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