On Thursday 21 January 2010, KOSAKI Motohiro wrote: > > > Hi Rafael, > > > > > > Do you mean this is the unrelated issue of nVidia bug? > > > > The nvidia driver _is_ buggy, but Maxim said he couldn't reproduce the > > problem if all the allocations made by the nvidia driver during suspend > > were changed to GFP_ATOMIC. > > > > > Probably I haven't catch your point. I don't find Maxim's original bug > > > report. Can we share the test-case and your analysis detail? > > > > The Maxim's original report is here: > > https://lists.linux-foundation.org/pipermail/linux-pm/2010-January/023982.html > > > > and the message I'm referring to is at: > > https://lists.linux-foundation.org/pipermail/linux-pm/2010-January/023990.html > > Hmmm... > > Usually, Increasing I/O isn't caused MM change. either subsystem change > memory alloc/free pattern and another subsystem receive such effect ;) > I don't think this message indicate MM fault. > > And, 2.6.33 MM change is not much. if the fault is in MM change > (note: my guess is no), The most doubtful patch is my "killing shrink_all_zones" > patch. If old shrink_all_zones reclaimed memory much rather than required. > The patch fixed it. IOW, the patch can reduce available free memory to be used > buggy .suspend of the driver. but I don't think it is MM fault. > > As I said, drivers can't use memory freely as their demand in suspend method. > It's obvious. They should stop such unrealistic assumption. but How should we fix > this? > - Gurantee suspend I/O device at last? > - Make much much free memory before calling .suspend method? even though > typical drivers don't need. That doesn't help already. Maxim tried to increase SPARE_PAGES (in kernel/power/power.h) and that had no effect. > - Ask all drivers how much they require memory before starting suspend and > Make enough free memory at first? That's equivalent to reworking all drivers to allocate memory before suspend eg. with the help of PM notifiers. Which IMHO is unrealistic. > - Or, do we have an alternative way? The $subject patch? > Probably we have multiple option. but I don't think GFP_NOIO is good > option. It assume the system have lots non-dirty cache memory and it isn't > guranteed. Basically nothing is guaranteed in this case. However, does it actually make things _worse_? What _exactly_ does happen without the $subject patch if the system doesn't have non-dirty cache memory and someone makes a GFP_KERNEL allocation during suspend? Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
