On Mon, 17 Sep 2007 15:04:05 +0100 Anton Altaparmakov <aia21@xxxxxxxxx>
wrote:
They files are attached this time rather than inlined so people don't complain about line wrapping! (No doubt people will not complain about them being attached! )-:)
I switched mailer after I learnt about flowed stuffs. Still,
appreciated.
If I read it correctly it appears all of low memory is eaten up by buffer_heads.
<quote>
# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>
: tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_s
labs> <sharedavail>
buffer_head 12569528 12569535 56 67 1 : tunables 120 60 8 :
slabdata 187605 187605 0
</quote>
That is 671MiB of low memory in buffer_heads.
But why is the kernel not reclaiming them by getting rid of the page cache pages they are attached to or even leaving the pages around but killing their buffers?
Well, you see, you have this very odd configuration where:
11GB highmem
1GB normal
pagecache pages go into highmem
buggerheads go into normal
I'm guessing there is no pressure at all on zone_highmem so the
kernel will not try to reclaim pagecache. And because the pagecache
pages are happily sitting there, the buggerheads are pinned and do not
get reclaimed.