linux-kernel - Re: [RFC PATCH 1/3] kmemleak: Allow partial freeing of memory blocks

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Message-Id: <1247035243.15919.28.camel@penberg-laptop>
Date:	Wed, 08 Jul 2009 09:40:43 +0300
From:	Pekka Enberg <penberg@...helsinki.fi>
To:	Catalin Marinas <catalin.marinas@....com>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...e.hu>, akpm@...ux-foundation.org
Subject: Re: [RFC PATCH 1/3] kmemleak: Allow partial freeing of memory
 blocks

On Tue, 2009-07-07 at 14:39 +0100, Catalin Marinas wrote:
> @@ -552,8 +557,27 @@ static void delete_object(unsigned long ptr)
>  	 */
>  	spin_lock_irqsave(&object->lock, flags);
>  	object->flags &= ~OBJECT_ALLOCATED;
> +	start = object->pointer;
> +	end = object->pointer + object->size;
> +	min_count = object->min_count;
>  	spin_unlock_irqrestore(&object->lock, flags);
>  	put_object(object);
> +
> +	if (!size)
> +		return;
> +
> +	/*
> +	 * Partial freeing. Just create one or two objects that may result
> +	 * from the memory block split. Note that partial freeing is only done
> +	 * by free_bootmem() and this happens before kmemleak_init() is
> +	 * called. The path below is only executed during early log recording
> +	 * in kmemleak_init(), so GFP_KERNEL is enough.
> +	 */
> +	if (ptr > start)
> +		create_object(start, ptr - start, min_count, GFP_KERNEL);
> +	if (ptr + size < end)
> +		create_object(ptr + size, end - ptr - size, min_count,
> +			      GFP_KERNEL);
>  }

Looks good to me. I think it would be better to have
delete_object_full() and delete_object_part(), and extract the common
code to __delete_object() or something instead of passing the magic zero
from kmemleak_free().

In any case:

Acked-by: Pekka Enberg <penberg@...helsinki.fi>

			Pekka

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