On Oct 12, 2007, at 7:58 AM, Peter Zijlstra wrote:
On Fri, 2007-10-12 at 07:53 -0700, Arjan van de Ven wrote:
On Fri, 12 Oct 2007 12:50:22 +0200
The pages will still be read-only due to dirty tracking, so the
first write will still do page_mkwrite().
Which can SIGBUS, no?
Sure, but that is no different than any other mmap'ed write. I'm not
seeing how an mlocked region is special here.
I agree it would be nice if mmap'ed writes would have better error
reporting than SIGBUS, but such is life.
well... there's another consideration
people use mlock() in cases where they don't want to go to the
filesystem for paging and stuff as well (think the various iscsi
daemons and other things that get in trouble).. those kind of uses
really use mlock to avoid
1) IO to the filesystem
2) Needing memory allocations for pagefault like things
at least for the more "hidden" cases...
prefaulting everything ready pretty much gives them that... letting
things fault on demand... nicely breaks that.
Non of that is changed. So I'm a little puzzled as to which side you
argue.
I think this might change the behavior in case you mlock sparse files.
I guess currently the holes disappear when you mlock them, but with
the patch the blocks wouldn't get allocated until they get written to.
-- Suleiman
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
