Messages in this thread | | | Date | Tue, 12 Aug 1997 17:21:45 -0400 (EDT) | From | Rob Hagopian <> | Subject | Re: Memory Management - BSD vs Linux |
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I like the Solaris method; we have a machine that uses one partition as both tmp space and swap... For people who need a few hundred megs of swap, it's there, but if you need a few hundred megs of tmp space, it's there... I believe that it's actually a filesystem in that there isn't a file visible that gets grown. For instance, we run mkstats on our web logs each week, late Sunday night. Last week we ran out of swap (not a pretty picture Monday morning). It would have been great if the visible tmp space went down while swap went up; nothing else runs then (and I doubt anyone's logged in) to use that space. During the rest of the week, we don't need that much swap and the tmp space is much more valuable. Granted, I could write a script to add extra swap before running the script, but that's really a rather poor fix... (fixing mkstats so it doesn't need so much memory OTOH...) -Rob H.
On Tue, 12 Aug 1997, Jacques Gelinas wrote:
> On 11 Aug 1997 thospel@mail.dma.be wrote: > > > > > In article <199708111305.PAA01801@cave.bitwizard.nl>, > > R.E.Wolff@BitWizard.nl (Rogier Wolff) writes: > > > Darren Reed wrote: > > >> > > >> In some mail I received from Theodore Y. Ts'o, sie wrote > > >> > > > >> > [3] Can any of these systems have > > >> > a) swap files rather than partitions > > >> > b) dynamically growing swap space? > > >> > As far as I can make out, the answeris no! > > >> > > > >> > Linux can swap to files (multiple files if necessary), and there is a > > >> > user-mode daemon that can allow you to dyanmically grow swap space (by > > >> > allocating a new file). > > >> > > >> NetBSD has swapfiles and does not require a daemon to be running for more > > >> to be added. NetBSD has also since moved on from just swap(2) to having > > > > > > So? That's dumb. Linux implements as much as possible in userspace. > > > Only things that have a genuine need to be in the kernel go in the > > > kernel. > > > > In principle, I agree. But I always wondered how well this really works. > > e.g. kernel suddenly needs a lot of swap, asks for it, oops, low, and > > the request fails before swapd got a chance to add this big file just > > waiting to be converted to swap. Or maybe swapd itself is swapped out, > > and to get it in again needs more swap than available. I would be VERY > > surprised if the simple solution of swapd was not full of races. > > > > anybody with deep knowledge about the memory management who can lay my > > fears to rest (or keep them awake) ? > > Adding swap dynamicly is a big lie. When you need the space, it is not > available because it has been taken by files. You can always limit files > to make sure that space will be available for swap, but then you are > better to allocate you swap immediatly. > > -------------------------------------------------------- > Jacques Gelinas (jacques@solucorp.qc.ca) > Linuxconf: The ultimate administration system for Linux. > see http://www.solucorp.qc.ca/linuxconf > new development: dhcp, disk quota management, virtual email accounts >
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