Re: [PATCH 1/5] staging: zsmalloc: zsmalloc memory allocation library

From: Nitin Gupta
Date: Mon Jan 23 2012 - 13:57:38 EST


On 01/20/2012 05:12 PM, Andrew Morton wrote:

> On Mon, 9 Jan 2012 16:51:56 -0600
> Seth Jennings <sjenning@xxxxxxxxxxxxxxxxxx> wrote:
>
>> This patch creates a new memory allocation library named
>> zsmalloc.
>
> I haven't really begun to look at this yet. The code is using many
> fields of struct page in new ways. This is key information for anyone
> to effectively review the code. So please carefully document (within
> the code itself) the ways in which the various page fields are used:
> semantic meaning of the overload, relationships between them, any
> locking rules or assumptions. Ditto any other data structures. This
> code should be reviewed very carefully by others so please implement it
> with that intention.
>


> It appears that a pile of dead code will be generated if CPU hotplug is
> disabled. (That's if it compiles at all!). Please take a look at users
> of hotcpu_notifier() - this facility cunningly causes all the hotplug code
> to vanish from vmlinux if it is unneeded.
>
>


ok, will look into these issues and add necessary documentation.


> afacit this code should be added to core mm/. Addition of code like
> this to core mm/ will be fiercely resisted on principle! Hence the
> (currently missing) justifications for adding it had best be good ones.
>


I don't think this code should ever get into mm/ since its just a driver
specific allocator. However its used by more than one driver (zcache and
zram) so it may be moved to lib/ or drivers/zsmalloc atmost?

Thanks,
Nitin
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