Nicholas Piggin <npig...@gmail.com> writes: > On Mon, 06 Nov 2017 16:14:10 +0530 > "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> wrote: > >> Nicholas Piggin <npig...@gmail.com> writes: >> >> > While mapping hints with a length that cross 128TB are disallowed, >> > MAP_FIXED allocations that cross 128TB are allowed. These are failing >> > on hash (on radix they succeed). Add an additional case for fixed >> > mappings to expand the addr_limit when crossing 128TB. >> >> Shouldn't that be fixed in radix. But i see x86 also doing this? >> >> >> if (flags & MAP_FIXED) >> return addr; >> >> Kiril, >> >> Is that expected? > > I should actually reply to this one because the other did not > have Kirill on cc. > > Generic mapping code appears it will always succeed when given an > explicit hint request, even if the address is below the boundary > and address + length is above it. Even when !MAP_FIXED. This is the > sane behaviour AFAIKS.
It's "sane" if you want the 128T boundary to be invisible. But the whole goddamn point was that we wanted apps to have to opt-in to using > 128T, and having brk accidentally go over the 128T boundary does not count as opting in. So it's a mess as usual. > So we should switch powerpc to match, shouldn't we? Yes we should do whatever the other arches do. Actually we should do what the man page describes .. except it doesn't. cheers