Subject: pagedeamon deadlocks (2)
To: None <,>
From: Gilbert Fernandes <>
List: current-users
Date: 02/19/2004 06:15:34

> Are you using lfs? The deadlock occurred to 
> me when I tried to extract a very large tarball
> on a lfs volume. Kernels between 2/14 and yesterday
> have the same problem. What's odd is, the samething
> was okay with a ffs (+softdep) partition.

using ffs. i got two boxes here. main
gate is running current-zg dated feb-12-2004
and i used it to compile a 1.6zj release for
my laptop. the zj pagedaemon goes in deadlock
when it tries to swap out and free pages == 0

i have spent the last hours over it. sadly,
my dsl link is very crappy and it took me some
time to grab the last src using cvs. i compiled
a 1.6zk kernel and just booted it. trying to
tar zxf a tar.gz of the 1.6zk src (220 mb)
gets me into ddb.

it's 7 am and i've not slept of the night
so i guess i'm gonna sleep for a few hours
now. as soon i'll wake up i will check
changes to that uvm part since zg and see
what changes could be doing this. there's
been a fix to weeks ago to a part of the
page daemon because it it was counting
in bytes and freeing in buffers and since
it looks like the most recent stuff i wondered
if other changes included in a commit could
be the last major change to uvm (trying to
find where to look, that is. call me a
lazy cow)

this is annoying. i upgraded my lovely
bsd because i wanted to fix an agp* trouble
with 830MP and i'm spending time on
something else. this is not moo. not moo
at all :/

i thought that the uvm would keep some
stuff to be able to allocate inodes
and always be able to swap out (we get
into uvm_pageout, buf_drain and buf_trim
to get into softdep-disk-io-initiation
and then uvm_km_kmemalloc1 is called
and the call to uvm_wait that follows
puts us into deadlock since we're
already waiting for pages to get freed
and if the pagedaemon cant even find
some by paging out.. moo stuck. moo.

well i have not yet read all those
uvm sources and once done we still
got to check last changes. you got some
free time to check san-moo ? :)
(so when i wake up you'll have fixed
this trouble he he)

Gilbert Fernandes