On Wed, Apr 13, 2011 at 05:05:33PM +0530, naveen yadav wrote: > 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 > Bear in mind that if you intend to depend on compaction to allow devices to use high-order allocations, you could be in trouble in the future. Compaction gives no guarantees that high-order pages will be available so a device must still be able to cope with allocation failure. In the case of transparent hugepage support and hugetlbfs, allocation failure is not a serious problem. > ****************************************************************************************************************************** > # 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 > ARM punches holes in the mem_map structure to save memory and memory compaction is not aware of them because it couldn't have been configured. Debug what PFN is failing and see if it is near a memory hole. If it's within a memory hole, that's your problem. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>