linux-kernel - Re: [Bug fix PATCH v2] Reusing a resource structure allocated by bootmem

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Date:	Tue, 16 Apr 2013 09:00:58 -0600
From:	Toshi Kani <toshi.kani@...com>
To:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, rientjes@...gle.com, linuxram@...ibm.com
Subject: Re: [Bug fix PATCH v2] Reusing a resource structure allocated by
 bootmem

On Tue, 2013-04-16 at 10:10 +0900, Yasuaki Ishimatsu wrote:
> When hot removing memory presented at boot time, following messages are shown:

 :

> The reason why the messages are shown is to release a resource structure,
> allocated by bootmem, by kfree(). So when we release a resource structure,
> we should check whether it is allocated by bootmem or not.
> 
> But even if we know a resource structure is allocated by bootmem, we cannot
> release it since SLxB cannot treat it. So for reusing a resource structure,
> this patch remembers it by using bootmem_resource as follows:
> 
> When releasing a resource structure by free_resource(), free_resource() checks
> whether the resource structure is allocated by bootmem or not. If it is
> allocated by bootmem, free_resource() adds it to bootmem_resource. If it is
> not allocated by bootmem, free_resource() release it by kfree().
> 
> And when getting a new resource structure by get_resource(), get_resource()
> checks whether bootmem_resource has released resource structures or not. If
> there is a released resource structure, get_resource() returns it. If there is
> not a releaed resource structure, get_resource() returns new resource structure
> allocated by kzalloc().
> 
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
> ---
> v2:
> Based on following Toshi's works:
>   Support memory hot-delete to boot memory
>     https://lkml.org/lkml/2013/4/10/469
>   resource: Update config option of release_mem_region_adjustable()
>     https://lkml.org/lkml/2013/4/11/694
> Added a NULL check into free_resource()
> Remove __free_resource()

Thanks for the update.  Looks good.  Can you also address Rui's comment?

-Toshi


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