This merges release-6.3 branch right before it was fully formatted.
There were quite a few conflicts that are resolved here. CoroFlow had
a check for OOM errors introduced in 6.3, but didn't seem applicable in
the new implmentation which seems to use boost.
This will stop eio threads for both the client (`fdb_stop_network()`)
and the server. This change is being done more for the former, but I
don't see any harm in doing the latter as well.
- Adds some asserts in KAIO to ensure that when knob is set, we don't
end up using KAIO in any case.
- Fixes a bug where we initialize AsyncFileKAIO on Linux builds even
when KAIO is disabled. This can cause problems in systems such as
Windows Subsystem for Linux where KAIO is not supported.
FIXES#2382
- Some Linux filesystems don't support O_DIRECT which is required by
Kernel AIO to function properly. Instead of using O_SYNC, EIO is
much better options in terms of performance penalty.
- Some systems may not support AIO at all. Eg. Windows Subsystem for
Linux.
FIXES#842
RELATED #274
Remove the use of relative paths. A header at foo/bar.h could be included by
files under foo/ with "bar.h", but would be included everywhere else as
"foo/bar.h". Adjust so that every include references such a header with the
latter form.
Signed-off-by: Robert Escriva <rescriva@dropbox.com>