Re: [PATCH] Re: Kernel Panic - 2.6.23-rc4-mm1 ia64 - was Re: Update: [Automatic] NUMA replicated pagecache ...

Lee Schermerhorn wrote:
On Wed, 2007-09-12 at 16:41 +0100, Andy Whitcroft wrote:
On Wed, Sep 12, 2007 at 11:09:47AM -0400, Lee Schermerhorn wrote:

Interesting, I don't see a memory controller function in the stack
trace, but I'll double check to see if I can find some silly race
condition in there.
right. I noticed that after I sent the mail.

Also, config available at:
http://free.linux.hp.com/~lts/Temp/config-2.6.23-rc4-mm1-gwydyr-nomemcont
Be interested to know the outcome of any bisect you do. Given its
tripping in reclaim.

Problem isolated to memory controller patches. This patch seems to fix
this particular problem. I've only run the test for a few minutes with
and without memory controller configured, but I did observe reclaim
kicking in several times. W/o this patch, system would panic as soon as
I entered direct/zone reclaim--less than a minute.


Thanks, excellent catch! The patch looks sane. Thanks for your help in
sorting this issue out. Hmm.. that means I never hit direct/zone reclaim
in my tests (I'll make a mental note to enhance my test cases to cover
this scenario).

Lee
--------------------------------

PATCH 2.6.23-rc4-mm1 Memory Controller: initialize all scan_controls'
isolate_pages member.

We need to initialize all scan_controls' isolate_pages member.
Otherwise, shrink_active_list() attempts to execute at undefined
location.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx>

mm/vmscan.c | 2 ++
1 file changed, 2 insertions(+)

Index: Linux/mm/vmscan.c
===================================================================
--- Linux.orig/mm/vmscan.c 2007-09-10 13:22:21.000000000 -0400
+++ Linux/mm/vmscan.c 2007-09-12 15:30:27.000000000 -0400
@@ -1758,6 +1758,7 @@ unsigned long shrink_all_memory(unsigned
.swap_cluster_max = nr_pages,
.may_writepage = 1,
.swappiness = vm_swappiness,
+ .isolate_pages = isolate_pages_global,
};

current->reclaim_state = &reclaim_state;
@@ -1941,6 +1942,7 @@ static int __zone_reclaim(struct zone *z
SWAP_CLUSTER_MAX),
.gfp_mask = gfp_mask,
.swappiness = vm_swappiness,
+ .isolate_pages = isolate_pages_global,
};
unsigned long slab_reclaimable;





--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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