On Sat 22-02-20 03:38:11, Cristopher Lameter wrote: > On Tue, 18 Feb 2020, Michal Hocko wrote: > > > Anyway, I do not think it is expected that kmalloc_node just blows up > > on those nodes. The page allocator simply falls back to the closest > > node. Something for kmalloc maintainers I believe. > > That is the case for an unconstrained allocation. kmalloc_node means that > you want memory from that node. And If there is no such node then it is an > error. Hmm, nasty. Is there any reason why kmalloc_node behaves differently from the page allocator? > > A short summary. kmalloc_node blows up when trying to allocate from a > > memory less node. > > Use kmalloc instead? And set a memory allocation policy? The current code (memcg_expand_one_shrinker_map resp. memcg_alloc_shrinker_maps) already use kvmalloc. Kirill's patch wanted to make those data structure on the respective node and kvmalloc_node sounded like the right thing to do. It comes as a surprise that the kernel simply blows up on a memory less node rather than falling back to a close node gracefully. I suspect this already happens when the target node is out of memory, right? How would a memory allocation policy help in this case btw.? -- Michal Hocko SUSE Labs
