Thread (5 messages) 5 messages, 3 authors, 2000-09-29

Re: 2.4.0-t9p7 and mmap002 - freeze

From: Mike Galbraith <hidden>
Date: 2000-09-28 06:31:56

On Wed, 27 Sep 2000, Roger Larsson wrote:
Hi,

Tried latest patch with the same result - freeze...
Ditto.
No extra patches added.
Ditto.
running from console as root
mmap002 from memtest-0.0.3
with RAMSIZE defined as 90 MB (I have 96MB)
after a while with heavy disk access (thrashing?) the drive
becomes silent - no more progress...
[if you can not repeat this - try with less memory 32 MB...]
I'm using a little proggy from Christoph Rohland (swptst.c), and
do not have to jump through any hoops to reproduce the freeze.
Magic works!

Magic memory
 Constantly LOW on inactive_clean (0 is the most common)
 lots of shared memory (almost equals active)
 [can be normal condition since mmap002 produces dirty
  mmaped pages]

Magic process:
  Manual samples gave the following locations.
  (NOTE: not a call trace)
If a kdb call trace will help (doubt it.. see below) I can post one.
  We are trying to clean pages, but do we make any
  progress since disk is silent?

Trace; c0127d85 <page_launder+3d/724>
Trace; c0126dad <deactivate_page_nolock+13d/248>
Trace; c0127e00 <page_launder+b8/724>
Trace; c0128035 <page_launder+2ed/724>
Trace; c0127dcc <page_launder+84/724>
Trace; c0127dd0 <page_launder+88/724>
Trace; c0127e00 <page_launder+b8/724>
Trace; c012fd38 <try_to_free_buffers+4/138>

Magic Sigterm (Alt+SysRq+E)
 Gives you a running system again.
Not here.  I looked at it with an IKD kernel, and here it's the same
loop as before.. __alloc_pages() running through try_again forever.
inactive_clean=0, a few pages bouncing between active and inactive_dirty.
__switch_to() never happens.  (though I can artificially yield and thus
make sysrq-e work.  Artificially scheduling only ensures that all other
tasks loop the same way. [coz inactive_clean=0.. page_launder() is always
failing to find something freeable])
Notes:
 Probably timing critical for entry into this state
 since adding a few printk:s makes it happen less often.
 I have even got complete mmap002 runs succeed - but
 disk is running too much and for too long time...
 a lot more than 10 min - normal run on previous testX
 did usually take less than 3 minutes.
I'm still at < 1 minute survival.. with many seconds to spare ;-)
I have yet to have a run succeed, though virgin source _does_ last
a bit longer (odd) than KDB enabled kernel.

	-Mike

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