EINTR while resizing dsm segment.

I provided the subject, and added -hackers.

> Hello,
> I am running postgres 11.5 and we were having issues with shared segments.
> So I increased the max_connection as suggested by you guys and reduced my
> work_mem to 600M.
>
> Right now instead, it is the second time I see this error :
>
> ERROR: could not resize shared memory segment "/PostgreSQL.2137675995" to
> 33624064 bytes: Interrupted system call

The function posix_fallocate is protected against EINTR.

| do
| {
| rc = posix_fallocate(fd, 0, size);
| } while (rc == EINTR && !(ProcDiePending || QueryCancelPending));

But not for ftruncate and write. Don't we need to protect them from
ENTRI as the attached?

--
Kyotaro Horiguchi
NTT Open Source Software Center