WARNING in xfs_lwr.c, xfs_write()

[Roman Kononov]

On Sun, 23 May 2010 23:12:24 -0500 Stan Hoeppner
<stan at hardwarefreak.com> wrote:
> "The whole notion of "direct IO" is totally braindamaged. Just say no.
...
> From:  http://lkml.org/lkml/2007/1/10/235

I definitely measure dramatic overall performance benefit using
O_DIRECT carefully.

In that thread, it is doubtful that madvise+mmap+msync allow
asynchronous zero-copy reads and writes to/from already pinned by a
device driver memory of data produced/consumed by that device, without
cache pollution and with intelligent handling of disk errors. Am I
wrong?

Thanks,

Roman