Re: Increasing swap limits

Lars Wirzenius (
Sun, 29 Sep 1996 18:00:50 +0300

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> However, from the docs and what I can understand in the
> source, Linux can only handle 1G of swap made up of a maximum of 8
> swapfiles or partitions of a maximum of 128M apiece.

Based on a direct question to Linus (who, me read sources? don't
be ridiculous), I wrote the following for the System Administrators'
Guide (which no-one else ever seems to quote -- yes I did search
AltaVista once):

The Linux memory manager limits the size of each swap space to
about 127~MB (for various technical reasons, the actual limit
is $(4096-10)\times 8\times 4096 = 133890048$ bytes, or
127.6875 megabytes). You can, however, use up to
16 swap spaces simultaneously, for a total of almost
2~GB.\footnote{A gigabyte here, a gigabyte there, pretty soon
we start talking about real memory.}

If the limit is really 8 swap spaces, I guess I need to correct it.
1.3.96's /usr/src/include/linux/swap.h does indeed have the line


but I don't know what that means.

Can someone confirm this?

Please read <> before mailing me.
Please don't Cc: me when replying to my message on a mailing list.

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