linux-kernel - Re: [PATCH 7/7] zram/xvmalloc: combine duplicate block delete code

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 31 Jan 2011 08:31:21 -0500
From:	Nitin Gupta <ngupta@...are.org>
To:	Greg Kroah-Hartman <gregkh@...e.de>,
	Pekka Enberg <penberg@...helsinki.fi>,
	devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 7/7] zram/xvmalloc: combine duplicate block delete code

On 01/28/2011 10:01 AM, Robert Jennings wrote:
> This patch eliminates duplicate code.  The remove_block_head function
> is a special case of remove_block which can be contained in remove_block
> without confusion.
>
> The portion of code in remove_block_head which was noted as "DEBUG ONLY"
> is now mandatory.  Doing this provides consistent management of the double
> linked list of blocks under a freelist and makes this consolidation
> of delete block code safe.  The first and last blocks will have NULL
> pointers in their previous and next page pointers respectively.
>
> Additionally, any time a block is removed from a free list the next and
> previous pointers will be set to NULL to avoid misuse outside xvmalloc.
>
> Signed-off-by: Robert Jennings<rcj@...ux.vnet.ibm.com>

The reason for introducing remove_block_head() as a separate function 
was to make malloc slightly faster but since I lack any profiling data, 
I'm not very sure if this may impact performance. Ideally, some sort of 
data with some malloc heavy test would have been useful. Anyways, I 
think major allocator changes will happen when we make xvmalloc 
allocated memory reclaimable, so maybe we can defer profiling.

Acked-by: Nitin Gupta <ngupta@...are.org>

Thanks,
Nitin
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/