Messages in this thread | | | Subject | Re: [PATCH] Use extents for recording what swap is allocated. | From | Nigel Cunningham <> | Date | Tue, 24 Oct 2006 09:04:10 +1000 |
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Hi.
On Mon, 2006-10-23 at 17:32 +0200, Pavel Machek wrote: > Hi! > > > Switch from bitmaps to using extents to record what swap is allocated; > > they make more efficient use of memory, particularly where the allocated > > storage is small and the swap space is large. > > > This is also part of the ground work for implementing support for > > supporting multiple swap devices. > > bitmaps were more efficient and longer than original code... I did not > _like_ them, but they are in now. I'd hate to change the code again, > for what, 0.5% gain?
0.5% of what? This is part of what is needed to implement support for multiple swap devices. You could extend what you already have, implementing bitmaps that require a bit for every page of swap the user has swapon'd, but that doesn't seem efficient to me.
> ...and this is still longer than bitmaps. > > And SNAPSHOT_GET_SWAP_PAGE seems to support multiple swap spaces > already.
It may do, but swap.c certainly doesn't. It supports exactly one device.
Regards,
Nigel
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