Hi! On Sat, Jun 28, 2025 at 12:55:26PM +0900, Simon Richter wrote: > On 28.06.25 10:54, Segher Boessenkool wrote: > >How do you disable memory overcommit? "Just" don't run problems that > >are bigger than you have memmory for? > > That is dependent on the kernel you use. On Linux, you would use the > "vm.overcommit_memory" sysctl: > > - a value of 0 (default) allows overcommit, but rejects some clearly > silly requests. Yup. Very conservative. But also usually the best choice. > So, something like > > # sysctl vm.overcommit_ratio=80 > # sysctl vm.overcommit_memory=2 > > should guarantee you that your compiles will either run at full speed, > or fail quickly, but as mentioned, that also applies to the rest of your > system -- if you are using systemd or a desktop environment, all of that > will *also* need to fit into physical RAM and cannot be swapped out even > if unused, but these tools are written with the assumption that having a > program loaded but not doing anything costs pretty much nothing because > unaccessed pages will be evicted as soon as something else needs them, > which is normally a reasonable assumption. > > So this solves the original problem, but is not optimal, because the > optimal behaviour would be to swap out other programs to give GCC more > space. Yeah. The only real solution is to just not have too little memoory :-) Segher
