sendfile(2) SF_NOPUSH flag proposal

[Terry Lambert]

Igor Sysoev wrote:
> > FreeBSD, NetBSD, OpenBSD, Darwin.
> 
> There's no sendfile() implementation in NetBSD and OpenBSD.  If you
> apply some experimental patch you can easy fix some non-portable issues.

Or you could just fix sendfile.  8-).


> By the way what's about kqueue(2) ?  Are you not confused that NetBSD
> does not support EVFILT_AIO and OpenBSD does not support EVFILT_AIO and
> EVFILT_TIMER ?  Does this mean that FreeBSD should not introduce any
> new kqueue filters or flags ?

These are incredibly trivial to support.  I estimate the work
at an hour each, including writing a unit test.  It took me
about an hour to write the SystemV IPC Message Queue KNOTE()
code for FreeBSD.


> I agree but I told not about the blocking on a page fault but the blocking
> on the reading the file page from a disk by sendfile(). These pages
> can be preloaded.

It doesn't "read" it, per se: it creates a mapping, and it
faults the pages; when they are in core, then they can be
sent.

[ removed 3 tangents not germane to this discussion; if you
  want to revive them, please revive them on -chat ]

-- Terry