On 10/03/2017 04:56 PM, Mike Kravetz wrote: > mmap(MAP_CONTIG) would have the following semantics: > - The entire mapping (length size) would be backed by physically contiguous > pages. > - If 'length' physically contiguous pages can not be allocated, then mmap > will fail. > - MAP_CONTIG only works with MAP_ANONYMOUS mappings. > - MAP_CONTIG will lock the associated pages in memory. As such, the same > privileges and limits that apply to mlock will also apply to MAP_CONTIG. > - A MAP_CONTIG mapping can not be expanded. Do you also need to lock out the NUMA migration APIs somehow? What about KSM (or does it already ignore VM_LOCKED)? > - At fork time, private MAP_CONTIG mappings will be converted to regular > (non-MAP_CONTIG) mapping in the child. As such a COW fault in the child > will not require a contiguous allocation. Maybe we should just define it as acting as if it had MADV_DONTFORK set on it, and also that it doesn't allow MADV_DONTFORK to be called on it. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
