Re: Found the commit that causes the OOMs

[Minchan Kim <minchan.kim@gmail.com>]

On Mon, Jun 29, 2009 at 11:21 PM, David Howells<dhowells@redhat.com> wrote:
> Wu Fengguang <fengguang.wu@intel.com> wrote:
>
>> Sorry! This one compiles OK:
>
> Sadly that doesn't seem to work either:
>
> msgctl11 invoked oom-killer: gfp_mask=0x200da, order=0, oom_adj=0
> msgctl11 cpuset=/ mems_allowed=0
> Pid: 30858, comm: msgctl11 Not tainted 2.6.31-rc1-cachefs #146
> Call Trace:
>  [<ffffffff8107207e>] ? oom_kill_process.clone.0+0xa9/0x245
>  [<ffffffff81072345>] ? __out_of_memory+0x12b/0x142
>  [<ffffffff810723c6>] ? out_of_memory+0x6a/0x94
>  [<ffffffff81074a90>] ? __alloc_pages_nodemask+0x42e/0x51d
>  [<ffffffff81080843>] ? do_wp_page+0x2c6/0x5f5
>  [<ffffffff810820c1>] ? handle_mm_fault+0x5dd/0x62f
>  [<ffffffff81022c32>] ? do_page_fault+0x1f8/0x20d
>  [<ffffffff812e069f>] ? page_fault+0x1f/0x30
> Mem-Info:
> DMA per-cpu:
> CPU    0: hi:    0, btch:   1 usd:   0
> CPU    1: hi:    0, btch:   1 usd:   0
> DMA32 per-cpu:
> CPU    0: hi:  186, btch:  31 usd:  38
> CPU    1: hi:  186, btch:  31 usd: 106
> Active_anon:75040 active_file:0 inactive_anon:2031
>  inactive_file:0 unevictable:0 dirty:0 writeback:0 unstable:0
>  free:1951 slab:41499 mapped:301 pagetables:60674 bounce:0
> DMA free:3932kB min:60kB low:72kB high:88kB active_anon:2868kB inactive_anon:384kB active_file:0kB inactive_file:0kB unevictable:0kB present:15364kB pages_scanned:0 all_unreclaimable? no
> lowmem_reserve[]: 0 968 968 968
> DMA32 free:3872kB min:3948kB low:4932kB high:5920kB active_anon:297292kB inactive_anon:7740kB active_file:0kB inactive_file:0kB unevictable:0kB present:992032kB pages_scanned:0 all_unreclaimable? no
> lowmem_reserve[]: 0 0 0 0
> DMA: 7*4kB 0*8kB 0*16kB 0*32kB 1*64kB 0*128kB 1*256kB 1*512kB 1*1024kB 1*2048kB 0*4096kB = 3932kB
> DMA32: 500*4kB 2*8kB 0*16kB 0*32kB 1*64kB 0*128kB 1*256kB 1*512kB 1*1024kB 0*2048kB 0*4096kB = 3872kB
> 1928 total pagecache pages
> 0 pages in swap cache
> Swap cache stats: add 0, delete 0, find 0/0
> Free swap  = 0kB
> Total swap = 0kB
> 255744 pages RAM
> 5589 pages reserved
> 238251 pages shared
> 216210 pages non-shared
> Out of memory: kill process 25221 (msgctl11) score 130560 or a child
> Killed process 26379 (msgctl11)

Totally, I can't understand this situation.
Now, this page allocation is order zero and It is just likely GFP_HIGHUSER.
So it's unlikely interrupt context.

Buddy already has enough fallback DMA32, I think.
Why kernel can't allocate page for order 0 ?
Is it allocator bug ?

-- 
Kinds regards,
Minchan Kim