> On Mon, Dec 02, 2024 at 12:07:01PM GMT, David Hildenbrand wrote: > > Likely it's best to look into reserving a large VMA space using > mmap(MAP_PRIVATE|MA_ANON, PROT_NONE); it's reserved but inaccessible, so it > cannot get reallocated for different purposes. Then converting pieces of > that into actually usable shared anonymous memory (e.g., MAP_FIXED). Yes, we've considered this option, preparing an initial "reserving" mapping, then take pieces out of it for usage. As I've mentioned to Matthew, there seems to be arguments against this approach. In a few words: * The impact on OOM decisions is not clear (at least to me). * In certain cases this will be counted against a reservation limits, although we don't use the memory yet (e.g. with hugetlb insige a cgroup with hugetlb.2MB.rsvd.limit_in_bytes set).
