Re: [take12 0/3] kevent: Generic event handling mechanism.

On Wed, 23 Aug 2006 11:50:56 +0400
Evgeniy Polyakov [off-list ref] wrote:

On Wed, Aug 23, 2006 at 12:07:58AM -0700, Andrew Morton (akpm@osdl.org) wrote:

quoted

On Wed, 23 Aug 2006 10:56:59 +0400
Evgeniy Polyakov [off-list ref] wrote:

quoted

On Wed, Aug 23, 2006 at 02:43:50AM +0200, Jari Sundell (sundell.software@gmail.com) wrote:

quoted

Actually, I didn't miss that, it is an orthogonal issue. A timespec
timeout parameter for the syscall does not imply the use of timespec
in any timer event, etc. Nor is there any timespec timer in kqueue's
struct kevent, which is the only (interface related) thing that will
be exposed.

void * in structure exported to userspace is forbidden.
long in syscall requires wrapper in per-arch code (although that
workaround _is_ there, it does not mean that broken interface should 
be used).
poll uses millisecods - it is perfectly ok.

I wonder whether designing-in a millisecond granularity is the right thing
to do.  If in a few years the kernel is running tickless with high-res clock
interrupt sources, that might look a bit lumpy.

Switching it to a __u64 nanosecond counter would be basically free on
64-bit machines, and not very expensive on 32-bit, no?

I can put nanoseconds as timer interval too (with aligned_u64 as David
mentioned), and put it for timeout value too - 64 bit nanosecods ends up
with 58 years, probably enough.
Structures with u64 a really not so good idea.

OK.  One could do u32 seconds/u32 nsecs, but a simple aligned_u64 will be
better for 64-bit machines, and OK for 32-bit.