Messages in this thread | | | Date | Wed, 19 Aug 2009 19:18:19 +0900 | Subject | Re: abnormal OOM killer message | From | Minchan Kim <> |
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On Wed, Aug 19, 2009 at 11:44 AM, Minchan Kim<minchan.kim@gmail.com> wrote: > On Wed, 19 Aug 2009 10:41:51 +0900 > 우충기 <chungki.woo@gmail.com> wrote: > >> Hi all~ >> I have got a log message with OOM below. I don't know why this >> phenomenon was happened. >> When direct reclaim routine(try_to_free_pages) in __alloc_pages which >> allocates kernel memory was failed, >> one last chance is given to allocate memory before OOM routine is executed. >> And that time, allocator uses ALLOC_WMARK_HIGH to limit watermark. >> Then, zone_watermark_ok function test this value with current memory >> state and decide 'can allocate' or 'cannot allocate'. >> >> Here is some kernel source code in __alloc_pages function to understand easily. >> Kernel version is 2.6.18 for arm11. Memory size is 32Mbyte. And I use >> compcache(0.5.2). >> ------------------------------------------------------------------------------------------------------------------------------------------------------------- >> ... >> did_some_progress = try_to_free_pages(zonelist->zones, >> gfp_mask); <== direct page reclaim >> >> p->reclaim_state = NULL; >> p->flags &= ~PF_MEMALLOC; >> >> cond_resched(); >> >> if (likely(did_some_progress)) { >> page = get_page_from_freelist(gfp_mask, order, >> zonelist, alloc_flags); >> if (page) >> goto got_pg; >> } else if ((gfp_mask & __GFP_FS) && !(gfp_mask & >> __GFP_NORETRY)) { <== when fail to reclaim >> /* >> * Go through the zonelist yet one more time, keep >> * very high watermark here, this is only to catch >> * a parallel oom killing, we must fail if we're still >> * under heavy pressure. >> */ >> page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, >> order, <== this is last chance >> zonelist, >> ALLOC_WMARK_HIGH|ALLOC_CPUSET); <== uses >> ALLOC_WMARK_HIGH >> if (page) >> goto got_pg; >> >> out_of_memory(zonelist, gfp_mask, order); >> goto restart; >> } >> ... >> ------------------------------------------------------------------------------------------------------------------------------------------------------------- >> >> In my case, you can see free pages(6804KB) is much more higher than >> high watermark value(1084KB) in OOM message. >> And order of allocating is also zero.(order=0) >> In buddy system, the number of 4kbyte page is 867. >> So, I think OOM can't be happend. >> > > Yes. I think so. > > In that case, even we can also avoid zone defensive algorithm. > >> How do you think about this? >> Is this side effect of compcache? > > I don't know compcache well. > But I doubt it. Let's Cced Nitin. > >> Please explain me. >> Thanks. >> >> This is OOM message. >> ------------------------------------------------------------------------------------------------------------------------------------------------------------- >> oom-killer: gfp_mask=0x201d2, order=0 (==> __GFP_HIGHMEM, >> __GFP_WAIT, __GFP_IO, __GFP_FS, __GFP_COLD) >> [<c00246c0>] (dump_stack+0x0/0x14) from [<c006ba68>] (out_of_memory+0x38/0x1d0) >> [<c006ba30>] (out_of_memory+0x0/0x1d0) from [<c006d4cc>] >> (__alloc_pages+0x244/0x2c4) >> [<c006d288>] (__alloc_pages+0x0/0x2c4) from [<c006f054>] >> (__do_page_cache_readahead+0x12c/0x2d4) >> [<c006ef28>] (__do_page_cache_readahead+0x0/0x2d4) from [<c006f594>] >> (do_page_cache_readahead+0x60/0x64) >> [<c006f534>] (do_page_cache_readahead+0x0/0x64) from [<c006ac24>] >> (filemap_nopage+0x1b4/0x438) >> r7 = C0D8C320 r6 = C1422000 r5 = 00000001 r4 = 00000000 >> [<c006aa70>] (filemap_nopage+0x0/0x438) from [<c0075684>] >> (__handle_mm_fault+0x398/0xb84) >> [<c00752ec>] (__handle_mm_fault+0x0/0xb84) from [<c0027614>] >> (do_page_fault+0xe8/0x224) >> [<c002752c>] (do_page_fault+0x0/0x224) from [<c0027900>] >> (do_DataAbort+0x3c/0xa0) >> [<c00278c4>] (do_DataAbort+0x0/0xa0) from [<c001fde0>] >> (ret_from_exception+0x0/0x10) >> r8 = BE9894B8 r7 = 00000078 r6 = 00000130 r5 = 00000000 >> r4 = FFFFFFFF >> Mem-info: >> DMA per-cpu: >> cpu 0 hot: high 6, batch 1 used:0 >> cpu 0 cold: high 2, batch 1 used:1 >> DMA32 per-cpu: empty >> Normal per-cpu: empty >> HighMem per-cpu: empty >> Free pages: 6804kB (0kB HighMem) >> Active:101 inactive:1527 dirty:0 writeback:0 unstable:0 free:1701 >> slab:936 mapped:972 pagetables:379 >> DMA free:6804kB min:724kB low:904kB high:1084kB active:404kB >> inactive:6108kB present:32768kB pages_scanned:0 all_unreclaimable? no >> lowmem_reserve[]: 0 0 0 0 >> DMA32 free:0kB min:0kB low:0kB high:0kB active:0kB inactive:0kB >> present:0kB pages_scanned:0 all_unreclaimable? no >> lowmem_reserve[]: 0 0 0 0 >> Normal free:0kB min:0kB low:0kB high:0kB active:0kB inactive:0kB >> present:0kB pages_scanned:0 all_unreclaimable? no >> lowmem_reserve[]: 0 0 0 0 >> HighMem free:0kB min:128kB low:128kB high:128kB active:0kB >> inactive:0kB present:0kB pages_scanned:0 all_unreclaimable? no >> lowmem_reserve[]: 0 0 0 0 >> DMA: 867*4kB 273*8kB 36*16kB 2*32kB 0*64kB 0*128kB 0*256kB 1*512kB >> 0*1024kB 0*2048kB 0*4096kB = 6804kB >> DMA32: empty >> Normal: empty >> HighMem: empty >> Swap cache: add 4597, delete 4488, find 159/299, race 0+0 >> Free swap = 67480kB >> Total swap = 81916kB > > In addition, total swap : 79M?? > >> Free swap: 67480kB >> 8192 pages of RAM >> 1960 free pages >> 978 reserved pages >> 936 slab pages >> 1201 pages shared >> 109 pages swap cached > > free page : 6M > page table + slab + reserved : 8M > active + inacive : 6M > > Where is 12M? > >> Out of Memory: Kill process 47 (rc.local) score 849737 and children. >> Out of memory: Killed process 49 (CTaskManager). >> Killed >> SW image is stopped.. >> script in BOOT is stopped... >> Starting pid 348, console /dev/ttyS1: '/bin/sh' >> -sh: id: not found >> # >> ------------------------------------------------------------------------------------------------------------------------------------------------------------- > > As you mentioned, your memory size is 32M and you use compcache. > How is swap size bigger than your memory size ? > Is the result of compression of swap pages ? > Nitin. Could you answer the question? > > I can't imagine whey order 0 allocation failed although there are > many pages in buddy. > > What do you mm guys think about this problem ?
I can only think that zonelists set up wrongly or freelist got damaged. Could you print your zonelist about __GFP_HIGHMEM ?
> -- > Kind regards, > Minchan Kim >
-- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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