Hello,

since neither Understanding the Linux VMM nor the kernelnewbies ML could
help me, I am takin the problem here:

I have a IBM Thinkpad 600X and use the suspend to disk feature (called
hibernation) when carring the notebook around, but writing ~600MB to the
disk takes a while.

After finding out, that the bios does only write used pages to disk, I
wrote a small userspace programm called mhog (see attached mhog.c), that
allocates roughly as many pages as used by the page cache. mhog retrieves
the number of pages to allocate from /proc/meminfo.

This works find, but does take a while, so I wrote a kernel module
(see attached nocache.c) to do the same. During module initilization I
simply loop around a get_free_page(GFP_NIO) to get all pages that can be
discarded, and upon the first failure I free all reserved pages again and
return -ENOMEM.

The kernel module does not speed up hibernation (pages are freed just
fine), but something must be diffrent between userspace and kernelspace
page allocation. I suspect the TLB, but did not find a hint on which of the
many tlb flushing calls to use.

So what am I missing?

thanks in advance
        Stefan

-- 
Stefan Volkel                            stefan.voelkel@millenux.com
Millenux GmbH                              mobile: +49.170.79177.17
Lilienthalstrasse 2                          phone: +49.711.88770.300
70825 Stuttgart-Korntal                       fax: +49.711.88770.349
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