Re: [BUG] Slow SATA disk - waiting in balance_dirty_pages() on i686-pae.html

From: Michal Hocko
Date: Wed Aug 02 2017 - 08:29:09 EST

On Tue 01-08-17 12:32:40, Philipp Hahn wrote:
> Hello,
> ;TL,DR: apt-get is blocked by balance_dirty_pages() with linux-{3,16
> 4.2, 4.9}, but fast after reboot.
> We still have several systems running 4.9.0-ucs104-686-pae. They have 16
> GiB RAM and two disk:

I would strongly discourage you from using 32b system with so much
memory. This will always bump into problems because of the inherent
kernel/userspace split. Also I would bet that the problem you are seeing
is the lack of lowmem memory which is considered for the dirty writers
throttling unless you have vm.highmem_is_dirtyable is set to 1 which is
not the case in your setup.
Michal Hocko