>The reason - tadaam - is so silly that it's embarrassing. The thing is,
>that the things that should use GFP_USER don't. They use GFP_KERNEL
I thought to change that but I was not sure (and infact some email ago I
asked that to you too). I have not changed that myself because I was
worryed that userspace allocation could be too much light. It would be
nice to know if using GFP_USER and disabling kswapd (at the end of
vmscan.c) causes process to segfaults (so that we can know if a real time
process can alloc/swapout memory safely).
My FP_IMPOSSIBLE code works fine here and detect the OOM perfectly. My
__get_free_pages() handle the GFP_USER allocation fine too, the only
differences is that it returns 0 when the machine is really really OOM
(even if there is some unused page). The point now is that using GFP_USER
for the userspace memory allocation sure works but _maybe_ is hiding an
_eventually_ possible deadlock. Right now I have no idea on how to
reproduce the deadlock using device drivers or network, maybe it' s really
impossible...
Right now I am rejecting the FP_* code from my tree though.
Andrea Arcangeli
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