[ARM] Issue of memory compaction on kernel 2.6.35.9

[yad.naveen@gmail.com (naveen yadav)]

Dear all,

we want to varify compaction on ARM and we are ?using 2.6.25.9 kernel
on cortex a9.

Since ARM does not have HUGETLB_PAGE support and compaction is HUGE
PAGE independent so I removed from config file

******************************************************************************************************************************
# support for memory compaction
config COMPACTION
? ? ? ?bool "Allow for memory compaction"
? ? ? ?select MIGRATION
? ? ? ?#depends on EXPERIMENTAL && HUGETLB_PAGE && MMU
? ? ? ?depends on EXPERIMENTAL && MMU
? help
? ? ? ? ?Allows the compaction of memory for the allocation of huge pages.
******************************************************************************************************************************
after triggering Memory Compaction by writing any value to
/proc/sys/vm/compact_memory?i am getting the SVC?mode crash
******************************************************************************************************************************
#echo 1 > /proc/sys/vm/compact_memory
Unable to handle kernel paging request at virtual address ee420be4
pgd = d9c6c000
[ee420be4] *pgd=00000000
Internal error: Oops: 805 [#1] PREEMPT
last sysfs file:
Modules linked in:
CPU: 0??? Not tainted? (2.6.35.9 #16)
PC is at compact_zone+0x178/0x610
LR is at compact_zone+0x138/0x610
pc : [<c009f30c>]??? lr : [<c009f2cc>]??? psr: 40000093
sp : d9d75e40? ip : c0380978? fp : d9d75e94
r10: d9d74000? r9 : c03806c8? r8 : 00069704
r7 : 00069800? r6 : 00d2e080? r5 : c04ea080? r4 : d9d75e9c
r3 : 60000093? r2 : 00000002? r1 : ee420be4? r0 : ee430b82
Flags: nZcv? IRQs off? FIQs on? Mode SVC_32? ISA ARM? Segment us
******************************************************************************************************************************


We ?tried to narrow down the prob... I found crash is form
?del_page_from_lru_list(zone, page, page_lru(page)); ? function
isolate_migratepages

{
-----------
/* Successfully isolated */
? ? ? ? ? ? ? ?del_page_from_lru_list(zone, page, page_lru(page));

? ? ? ?--------------------------------------------------
}

In my ARM board have only one zone (Node 0, zone???Normal)

******************************************************************************************************************************
VDLinux#> cat /proc/buddyinfo
Node 0, zone ? Normal ? ? ?5 ? ? ?4 ? ? ?4 ? ? ?2 ? ? ?1 ? ? ?3 ? ? ?0
? ? 2 ??????3??????4??????2??????1??????7
******************************************************************************************************************************

Can some one guide why I am geeting the crash and how to debugg this problem


Thanks