On Wed 24-06-15 10:27:36, Vlastimil Babka wrote: > [add some CC's] > > On 06/19/2015 05:16 PM, Mark Hills wrote: [...] > > The system is an HP xw6600, running i686 kernel. This happens whether How many CPUs does the machine have? > > internal SATA HDD, SSD or external USB drive is used. I first saw this on > > kernel 4.0.4, and 4.0.5 is also affected. OK so this is 32b kernel which might be the most important part. What is the value of /proc/sys/vm/highmem_is_dirtyable? Also how does your low mem vs higmem look when you are setting the ratio (cat /proc/zoneinfo)? It seems Vlastimil is right and a bogus ratelimit_pages is calculated and your writers are throttled every few pages. -- Michal Hocko SUSE Labs -- 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>