On Wed, Jul 01, 2015 at 04:17:10PM +0200, Peter Zijlstra wrote: > On Wed, Jul 01, 2015 at 07:00:31AM -0700, Paul E. McKenney wrote: > > > That is a bit extreme, Peter. > > Of course; but I'm really not seeing people taking due care with them
;-) > > Are a huge pile of them coming in this merge window or something? > > What raised your concerns on this issue? > > This is complete horse manure (breaking the nvidiot binary blob is a > good thing): > > 74b51ee152b6 ("ACPI / osl: speedup grace period in acpi_os_map_cleanup") Really??? I am not concerned about this one. After all, one of the first things that people do for OS-jitter-sensitive workloads is to get rid of binary blobs. And any runtime use of ACPI as well. And let's face it, if your latency-sensitive workload is using either binary blobs or ACPI, you have already completely lost. Therefore, an additional expedited grace period cannot possibly cause you to lose any more. > Also, I'm not entirely convinced things like: > > fd2ed4d25270 ("dm: add statistics support") > 83d5e5b0af90 ("dm: optimize use SRCU and RCU") > ef3230880abd ("backing-dev: use synchronize_rcu_expedited instead of > synchronize_rcu") > > Are in the 'never' happens category. Esp. the backing-dev one, it > triggers every time you unplug a USB stick or similar. Which people should be assiduously avoiding for any sort of industrial-control system, especially given things like STUXNET. > Rejigging a DM might indeed be rare enough; but then again, people use > DM explicitly so they can rejig while in operation. They rejig DM when running OS-jitter-sensitive workloads? > Also, they really do not explain how expedited really is the only option > available. Why things can't be batched etc.. Fair question! Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/