On 2016-06-02 18:15:54 +0100, Greg Stark wrote: > I just threw maxalign everywhere but I was going to comment that we > might need to put a double in for the subsequent struct elements to > end up aligned as well.
Hm. Shouldn't be needed if you MAXALIGN the sz computation, because that'll mean each struct will start at the proper offset. > But I guess that's not true due to the u64 > element. I'm not sure I've completely grokked all the bits and pieces > here so I may have added a few too many maxaligns. I put them on all > the size and offset calculations before the multiplications. They should be *after* the multiplications. If arrays of structs are internally misaligned there's nothing we can do. > diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c > index 3fbe0e5..5e69a5a 100644 > --- a/src/backend/storage/ipc/latch.c > +++ b/src/backend/storage/ipc/latch.c > @@ -485,35 +485,35 @@ CreateWaitEventSet(MemoryContext context, int nevents) > char *data; > Size sz = 0; > > - sz += sizeof(WaitEventSet); > - sz += sizeof(WaitEvent) * nevents; > + sz += MAXALIGN(sizeof(WaitEventSet)); > + sz += MAXALIGN(sizeof(WaitEvent)) * nevents; > > #if defined(WAIT_USE_EPOLL) > - sz += sizeof(struct epoll_event) * nevents; > + sz += MAXALIGN(sizeof(struct epoll_event)) * nevents; So this needs to include the '* nevents' inside the MAXALIGN. > #elif defined(WAIT_USE_POLL) > - sz += sizeof(struct pollfd) * nevents; > + sz += MAXALIGN(sizeof(struct pollfd)) * nevents; Same. > #elif defined(WAIT_USE_WIN32) > /* need space for the pgwin32_signal_event */ > - sz += sizeof(HANDLE) * (nevents + 1); > + sz += MAXALIGN(sizeof(HANDLE)) * (nevents + 1); > #endif same. > > #if defined(WAIT_USE_EPOLL) > set->epoll_ret_events = (struct epoll_event *) data; > - data += sizeof(struct epoll_event) * nevents; > + data += MAXALIGN(sizeof(struct epoll_event)) * nevents; > #elif defined(WAIT_USE_POLL) > set->pollfds = (struct pollfd *) data; > - data += sizeof(struct pollfd) * nevents; > + data += MAXALIGN(sizeof(struct pollfd)) * nevents; > #elif defined(WAIT_USE_WIN32) > set->handles = (HANDLE) data; > - data += sizeof(HANDLE) * nevents; > + data += MAXALIGN(sizeof(HANDLE)) * nevents; > #endif same. Want me to polish that up and push, or do you want to go back and forth and push yourself? Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
