On Friday 22 January 2010, KOSAKI Motohiro wrote: > > > 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_? > > Hmm.. > Do you mean we don't need to prevent accidental suspend failure? > Perhaps, I did misunderstand your intention. If you think your patch solve > this this issue, I still disagree. No, I don't. > but If you think your patch mitigate the pain of this issue, I agree it. That's what I wanted to say really. > I don't have any reason to oppose your first patch. Great! > > 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? > > Page allocator prefer to spent lots time for reclaimable memory searching than > returning NULL. IOW, it can spent time few second if it doesn't have > reclaimable memory. > In typical case, OOM killer forcely make enough free memory if the system > don't have any memory. But under suspending time, oom killer is disabled. > So, if the caller (probably drivers) call alloc >1000times, the system > spent lots seconds. > > In this case, GFP_NOIO doesn't help. slowness behavior is caused by > freeable memory search, not slow i/o. > > However, if strange i/o device makes any i/o slowness, GFP_NOIO might help. > In this case, please don't ask me about i/o thing. I don't know ;) OK, thanks for the explanation. Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
