Re: decode GFP flags in oom killer output.

[Jesper Juhl]

On Wed, 7 Mar 2012, Dave Jones wrote:

> Decoding these flags by hand in oom reports is tedious,
> and error-prone.
> 
> Signed-off-by: Dave Jones <davej@xxxxxxxxxx>
> 
> diff -durpN '--exclude-from=/home/davej/.exclude' -u src/git-trees/kernel/linux/include/linux/gfp.h linux-dj/include/linux/gfp.h
> --- linux/include/linux/gfp.h	2012-01-11 16:54:21.736395499 -0500
> +++ linux-dj/include/linux/gfp.h	2012-03-06 13:17:37.294692113 -0500
> @@ -10,6 +10,7 @@
>  struct vm_area_struct;
>  
>  /* Plain integer GFP bitmasks. Do not use this directly. */
> +/* Update mm/oom_kill.c gfp_flag_texts when adding to/changing this list */
>  #define ___GFP_DMA		0x01u
>  #define ___GFP_HIGHMEM		0x02u
>  #define ___GFP_DMA32		0x04u
> diff -durpN '--exclude-from=/home/davej/.exclude' -u src/git-trees/kernel/linux/mm/oom_kill.c linux-dj/mm/oom_kill.c
> --- linux/mm/oom_kill.c	2012-01-17 17:54:14.541881964 -0500
> +++ linux-dj/mm/oom_kill.c	2012-03-06 13:17:44.071680535 -0500
> @@ -416,13 +416,40 @@ static void dump_tasks(const struct mem_
>  	}
>  }
>  
> +static unsigned char *gfp_flag_texts[32] = {
> +	"DMA", "HIGHMEM", "DMA32", "MOVABLE",
> +	"WAIT", "HIGH", "IO", "FS",
> +	"COLD", "NOWARN", "REPEAT", "NOFAIL",
> +	"NORETRY", NULL, "COMP", "ZERO",
> +	"NOMEMALLOC", "HARDWALL", "THISNODE", "RECLAIMABLE",
> +	NULL, "NOTRACK", "NO_KSWAPD", "OTHER_NODE",
> +};

Hmm, there are 24 entries in this list, yet you allocate an array of size 
32 - why?
Shouldn't this just be 'static unsigned char *gfp_flag_texts[] = {...}' 
and let the compiler worry about the size? Or am I overlooking something 
obvious?

-- 
Jesper Juhl <jj@xxxxxxxxxxxxx>       http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
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