On Fri, Sep 16, 2022 at 05:11:18PM -0700, Kees Cook wrote: > The interaction with sched_exec() should be no worse (the file is opened > before it in either case), but in reading that function, it talks about > taking the opportunity to move the process to another CPU (IIUC) since, > paraphrasing, "it is at its lowest memory/cache size." But I wonder if > there is an existing accidental pessimistic result in that the process > stack has already been allocated. I am only passingly familiar with how > tasks get moved around under NUMA -- is the scheduler going to move > this process onto a different NUMA node and now it will be forced to > have the userspace process stack on one node and the program text and > heap on another? Or is that totally lost in the noise? Probably noise; text is going to be a crap-shoot anyway due to DSOs only having a single copy in the page-cache. And the stack will be relatively small at this point and also, numa-balance can migrate those pages around if they matter. > More specifically, I was wondering if processes would benefit from having > sched_exec() moved before the mm creation? Can't hurt I think.
