Re: swapping and oom-killer: gfp_mask=0x201d2, order=0

[Mike Galbraith <efault@gmx.de>]

On Sat, 2006-05-13 at 15:11 +0300, Al Boldi wrote:
> Mike Galbraith wrote:
> > On Fri, 2006-05-12 at 15:17 +0300, Al Boldi wrote:
> > > Note that this is not specific to mem=8M, but rather a general oom
> > > observation even for mem=4G, where it is only much later to occur.
> >
> > An oom situation with 4G ram would be more interesting than this one.
> 
> Agreed, but can you tell me what readahead has to do with this oom?
> 
> oom-killer: gfp_mask=0x201d2, order=0
>  [<c013ff25>] out_of_memory+0xa5/0xc0
>  [<c0141099>] __alloc_pages+0x279/0x310
>  [<c0143669>] __do_page_cache_readahead+0xe9/0x120
>  [<c0143b3f>] max_sane_readahead+0x2f/0x50
>  [<c013d8cb>] filemap_nopage+0x2eb/0x370
>  [<c0149ea5>] do_no_page+0x65/0x220
>  [<c014a1dc>] __handle_mm_fault+0xec/0x200
>  [<c0113258>] do_page_fault+0x188/0x5c5
>  [<c01130d0>] do_page_fault+0x0/0x5c5
>  [<c0103a0f>] error_code+0x4f/0x54

Nothing except that it asked for a page at a bad time, triggering the
bad-hair-day reaction.  That being said, the readahead allocation mask
should have probably included GFP_NORETRY.  (though with 8MB, if the
readahead didn't get you, the subsequent read probably would anyway)

	-Mike