Messages in this thread | | | Date | Wed, 18 Feb 1998 11:14:01 +0100 (MET) | From | Gabriel Paubert <> | Subject | Re: 2.1.87 Oopsen |
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On Tue, 17 Feb 1998, Tim Wright wrote:
> I went hunting for the widely reported oops in 2.1.87 and found the following. > The problem is the PROT_NONE changes, or rather the changes to the SWP_TYPE > and SWP_ENTRY macros. > SHM_SWP_TYPE is defined to be 0x40, so left shifting by two and then masking > to the bottom 8 bits loses badly :-(
[snipped]
> Since we now need 2 bits for the PAGE_PRESENT, I suspect changing the value of > SHM_SWP_TYPE in include/linux/swap.h to 0x20 should work (since MAX_SWAPFILES > is 8, and this seems to be the other use for the type part, I don't see a > clash). Alternatively, since the shared memory id and offset are currently > encoded in 22 bits for a shared memory page, the split could be changed to > 23:9 from 24:8, but I don't know all the repurcussions.
Beware of doing this, I remember that some people with large systems changed MAX_SWAPFILES from 8 to 16 because the current limit on swap space with 4kB pages (1Gb total, 128 Mb per file) is simply too small by today's standards, and the one I would like to see removed for 2.2 if possible.
Gabriel.
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