On Fri, 11 Jan 2013 12:46:15 +1100 paul.szabo@xxxxxxxxxxxxx wrote: > > ... I don't believe 64GB of RAM has _ever_ been booted on a 32-bit > > kernel without either violating the ABI (3GB/1GB split) or doing > > something that never got merged upstream ... > > Sorry to be so contradictory: > > psz@como:~$ uname -a > Linux como.maths.usyd.edu.au 3.2.32-pk06.10-t01-i386 #1 SMP Sat Jan 5 18:34:25 EST 2013 i686 GNU/Linux > psz@como:~$ free -l > total used free shared buffers cached > Mem: 64446900 4729292 59717608 0 15972 480520 > Low: 375836 304400 71436 > High: 64071064 4424892 59646172 > -/+ buffers/cache: 4232800 60214100 > Swap: 134217724 0 134217724 > psz@como:~$ > > (though I would not know about violations). > > But OK, I take your point that I should move with the times. Check /proc/slabinfo, see if all your lowmem got eaten up by buffer_heads. If so, you *may* be able to work around this by setting /proc/sys/vm/dirty_ratio really low, so the system keeps a minimum amount of dirty pagecache around. Then, with luck, if we haven't broken the buffer_heads_over_limit logic it in the past decade (we probably have), the VM should be able to reclaim those buffer_heads. Alternatively, use a filesystem which doesn't attach buffer_heads to dirty pages. xfs or btrfs, perhaps. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>