On Mon, 28 Oct 2024 14:13:26 +0000 Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> wrote: > Userland library functions such as allocators and threading implementations > often require regions of memory to act as 'guard pages' - mappings which, > when accessed, result in a fatal signal being sent to the accessing > process. > > The current means by which these are implemented is via a PROT_NONE mmap() > mapping, which provides the required semantics however incur an overhead of > a VMA for each such region. > > With a great many processes and threads, this can rapidly add up and incur > a significant memory penalty. It also has the added problem of preventing > merges that might otherwise be permitted. > > This series takes a different approach - an idea suggested by Vlasimil > Babka (and before him David Hildenbrand and Jann Horn - perhaps more - the Nit. s/Vlasimil/Vlastimil/ ;) Thanks, SJ [...]