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    SubjectRe: Multiple swap partition uglies (fwd)
    Hi Paul.

    >> Hang on - both partitions have been specified as "pri=1" there,
    >> and my understanding was that swap partitions have to have
    >> DIFFERENT priorities - also, on my system, all swap priorities are
    >> negative...

    > from man 2 swapon

    > Each swap area has a priority, either high or low. The
    > default priority is low. Within the low-priority areas,
    > newer areas are even lower priority than older areas.

    > All priorities set with swapflags are high-priority,
    > higher than default. They may have any non-negative value
    > chosen by the caller. Higher numbers mean higher prior-
    > ity.

    > Swap pages are allocated from areas in priority order,
    > highest priority first. For areas with different priori-
    > ties, a higher-priority area is exhausted before using a
    > !! lower-priority area. If two or more areas have the same
    > !! priority, and it is the highest priority available, pages
    > !! are allocated on a round-robin basis between them.

    Nods - but note the following paragraph...

    > As of Linux 1.3.6, the kernel usually follows these rules,
    > but there are exceptions.

    That appears to be referring to an OLD kernel - a VERY OLD one...but
    it's the same wording as the one on my system...

    > nuff said?

    Not sure...

    > and from man 8 swapon

    > -p priority
    > Specify priority for swapon. This option is only
    > available if swapon was compiled under and is used
    > under a 1.3.2 or later kernel. priority is a value
    > between 0 and 32767. See swapon(2) for a full
    > description of swap priorities. Add pri=value to
    > the option field of /etc/fstab for use with swapon
    > -a.

    > which _says_ the priorities are positive numbers. However, I've
    > seen posts with negative priorities mentioned, so I'm not really
    > sure.

    I seem to remember something relating to early in the 2.0 series
    (around 2.0.11 IIRR) where a bug was found to exist relating to swap
    areas with equal priorities, and I don't think it was ever tracked
    down, but the advice given then was NOT to use swap areas with equal

    >> That would tend to indicate a configuration error - especially
    >> since the system I run that has two swap partitions (with
    >> DIFFERENT priority levels) does NOT suffer from the problem, even
    >> though it otherwise matches the specification given in the
    >> original message...

    > What's wierd is that I don't seem to have any problems as long as
    > the swaps have different priorities (dosen't seem to matter which
    > is higher). Problem only seems to come up for priorities the same.
    > When I know more, I'll be posting back to linux-kernel.

    That sounds like the bug report mentioned above...

    Incidentally, my method of assigning [differing] priorities is simply
    to list the swap partitions in /etc/fstab in descending order of the
    priority with which I want them used, and let mount -a assign the
    relevant priorities at boot time. I get priorities of -2 and -3
    assigned on one system, and -1 and -2 on the other (I only have the
    two with multiple swap partitions)...

    Best wishes from Riley.

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