Hi, On Monday, 30 April 2007 16:24, Johannes Berg wrote: > Hi, > > Paul Mackerras noticed that even for suspend to ram we currently free > some memory in suspend_prepare. Is that necessary because we freeze > userspace so devices can allocate a bit of memory for suspend? I don't think it's related to the freezing of user space. You can allocate memory with all of the user space frozen just fine. I'd say it's related to the freezing of kernel threads, rather. > Why do we freeze userspace anyway? Well, let me quote Linus: "I _do_ realize the IO request queue issues, and that we cannot actually do s2ram with some devices in the middle of a DMA. So we want to be able to avoid *that*, there's no question about that. And I suspect that stopping user threads and then waiting for a sync is practically one of the easier ways to do so." Greetings, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
