linux-kernel - Re: [PATCH 05/37] kdb: core for kgdb back end

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Message-ID: <87y6ktb1p5.fsf@basil.nowhere.org>
Date:	Thu, 24 Dec 2009 02:28:06 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	Jason Wessel <jason.wessel@...driver.com>
Cc:	linux-kernel@...r.kernel.org, kgdb-bugreport@...ts.sourceforge.net,
	kdb@....sgi.com, mingo@...e.hu, mort@....com,
	linux-arch@...r.kernel.org
Subject: Re: [PATCH 05/37] kdb: core for kgdb back end

Jason Wessel <jason.wessel@...driver.com> writes:

I remember going with kaos through all the code
outside kdb/ in his own patch and for nearly all hooks
outside we found some way to eliminate them. 

I think a lot of this is here too.

>  
> +#ifdef	CONFIG_KGDB_KDB
> +/* Like meminfo_proc_show() but without the locks and using kdb_printf() */
> +void kdb_meminfo_proc_show(void)

Are there even any locks in meminfo_proc_show()? I don't see any on a quick look.
Ah or is that only for swap_info? That could be a flag or perhaps that
access can be even made lockless (it looks like it could)

I guess a better way would be to have a kdb specific seq file implementation
and then just use the normal function, instead of copying everything.

>  void get_vmalloc_info(struct vmalloc_info *vmi)
>  {
>  	struct vm_struct *vma;
>  	unsigned long free_area_size;
>  	unsigned long prev_end;
> +#ifdef CONFIG_KGDB_KDB
> +	int get_lock = !KDB_IS_RUNNING();
> +#else
> +#define	get_lock 1
> +#endif
> +

A standard way to do such would be a __get_vmalloc_info with the 
lock in the caller

Didn't read everything in this gigantic patch.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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