On Mon, Sep 19, 2016 at 12:13 PM, Jeroen Demeyer <[email protected]> wrote:
> On 2016-09-19 13:02, Jonathan Bober wrote: > >> If I ulimit -v 8 GB, say, (which is 512/64), and the PARI allocater >> immediately grabs 2 GB of the virtual address space for itself, then >> that seems like it leaves only 6 GB for malloc/sage_malloc/whatever >> else, which would be effectively limiting the physical memory available >> in some situations. >> > > Then use a larger value for "ulimit -v" or add some swap space. > > That doesn't really solve the problem, which I phrased poorly. The machine has an (antiquated) setup where, when a process requests X bytes of memory, the kernel reserves X bytes of physical memory for it. This is usually fine because users usually use the memory they request, and when they don't, well, there are 512 GB of it. But it does mean that every virtual memory allocation has a physical memory cost. (It also has benefits, like when someone screws up they usually notice immediately, instead of when the OOM killer kills sshd or the login process.) > This is not the default, and you probably wouldn't want to >> run your laptop this way >> > > But it is an advanced setting. Given that, I assume that you are clever > enough to do the right thing. With overcommit_memory set to 2, I'm not sure that there is a right thing to do. If I'm the only person in the world with this problem, then I should keep my mouth shut and get with the times, but I don't think this setup is so unreasonable. Anyway, where exactly is this allocation coming from? Is it a default PARI setting, or does it come from the way that Sage uses PARI? (I mean, to whom should I address my "hate mail"? :) > > -- > You received this message because you are subscribed to the Google Groups > "sage-support" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at https://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
