Noticed that Linux can lag?

[viking60]

Have you noticed that Linux can become unresponsive for a while when the system is under memory pressure and writing to a slow device?
F.ex. a dd command could produce it in combination with a slow USB.
Now it will be fixed. If we are lucky this will be history as of kernel 2.6.36 approximately by the end of this year.

Kernel patch to remove unresponsivenes

[dedanna1029]

Nice! Been waiting on something to cure it.

[rolf]

This happens when the two conditions are both meet:
- under memory pressure
- writing heavily to a slow device

Yes. There have been times when some lengthy operation is hogging resources, sometimes prodding me so far as 'man nice'. I've not got much further than looking, maybe one unsuccessful shot at 'renice', as these occasions get my attention only infrequently and becoming master of 'nice' is, also, a time consumer. It appears this patch will solve a particular subset of resource hogging and that will be nice. However, I suspect there are some programs, such as video en/decoding, that I use that will not show a change. I think there is another subset of 'rude' programs that take more resources than I need them to but, currently, to date, with a pretty spry machine, I will probably wait, a little, rather than try to teach manners (see above).

[viking60]

According to Phoronix this can be patched back to 2.6.32 so it will be of use for the LTS kernel users too.
http://www.phoronix.com/scan.php?page=n ... &px=ODQ3OQ
Well that is n.... good I guess