Re: hangs on boot in 9984d7394618df9

From: Nathan Zimmer
Date: Tue Apr 09 2013 - 13:12:42 EST


On 04/08/2013 06:46 PM, Doug Anderson wrote:
Al,

On Mon, Apr 8, 2013 at 4:06 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
Folks, see if vfs.git#experimental works for you; the PITA had apparently
been caused by change of open() semantics for /proc/<pid>/fd/<some_pipe> -
it started to behave like a FIFO, i.e. wait for peer to show up. Normally
that's not a problem, but if you have closed e.g. the write end of a pipe
and try to open /proc/<pid>/fd/<read_end_of_pipe>, you'll get open() waiting
for writers to appear. Which isn't what we used to do here (open succeeded
immediately) and apparently that was enough to trip drakut.

Branch head should be at 574179469f7370aadb9cbac1ceca7c3723c17bee.
That branch booted fine for me and didn't show any problems.

I wasn't easily able to merge onto linux-next and test there though.
I tried applying these the 4 top commits of your branch to
"next-20130408" and it didn't solve my problems. A full merge of your
branch to linux-next showed conflicts and I didn't dig.

-Doug
I booted great for me too.
Also the numbers from the scaling test are improved also, at least on my 128p box.
I'll verify on a 512 or larger box when I have the chance.
However I think I still should to provide some relief for the older kernels.
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