Comment 157 for bug 620074

I have have limited the usage of generic_file_aio_write in filemap.c for every process. Once I have limited the throughput of every process. When the overall throughput was below disc capacity, there where no more freezes of the mouse. When the overall throughput was above disc capacity, the problem appears immediately.

When I have limited the usage to max 20% of interval time for every process, and suspended the thread when it needs more. The problems was present as before, as every 20st requests, __generic_file_aio_write_nolock needs more than 2s for finishing.

I tried the same for the cfq scheduler in cfq_choose_req and added penalties for processes with heavy io, but the pid is not correctly set for all cfq_queue and I got a kernel panic after a while. Before the the kernel panic there was no improvement.