On Fri, Aug 28, 2020 at 02:07:12PM +0800, Xianting Tian wrote: > As the normal aio wait path(read_events() -> > wait_event_interruptible_hrtimeout()) doesn't account iowait time, so use > this patch to make it to account iowait time, which can truely reflect > the system io situation when using a tool like 'top'. Do be aware though that io_schedule() is potentially far more expensive than regular schedule() and io-wait accounting as a whole is a trainwreck. When in_iowait is set schedule() and ttwu() will have to do additional atomic ops, and (much) worse, PSI will take additional locks. And all that for a number that, IMO, is mostly useless, see the comment with nr_iowait(). But, if you don't care about performance, and want to see a shiny random number generator, by all means, use io_schedule().
