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    SubjectRe: [PATCH powerpc 2/2] kfree the cache name of pgtable cache if SLUB is used
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    On Fri, 2012-07-06 at 14:13 +0400, Glauber Costa wrote:
    > On 07/05/2012 01:29 PM, Li Zhong wrote:
    > > On Thu, 2012-07-05 at 12:23 +0400, Glauber Costa wrote:
    > >> On 07/05/2012 05:41 AM, Li Zhong wrote:
    > >>> On Wed, 2012-07-04 at 16:40 +0400, Glauber Costa wrote:
    > >>>> On 07/04/2012 01:00 PM, Li Zhong wrote:
    > >>>>> On Tue, 2012-07-03 at 15:36 -0500, Christoph Lameter wrote:
    > >>>>>>> Looking through the emails it seems that there is an issue with alias
    > >>>>>>> strings.
    > >>>>> To be more precise, there seems no big issue currently. I just wanted to
    > >>>>> make following usage of kmem_cache_create (SLUB) possible:
    > >>>>>
    > >>>>> name = some string kmalloced
    > >>>>> kmem_cache_create(name, ...)
    > >>>>> kfree(name);
    > >>>>
    > >>>> Out of curiosity: Why?
    > >>>> This is not (currently) possible with the other allocators (may change
    > >>>> with christoph's unification patches), so you would be making your code
    > >>>> slub-dependent.
    > >>>>
    > >>>
    > >>> For slub itself, I think it's not good that: in some cases, the name
    > >>> string could be kfreed ( if it was kmalloced ) immediately after calling
    > >>> the cache create; in some other case, the name string needs to be kept
    > >>> valid until some init calls finished.
    > >>>
    > >>> I agree with you that it would make the code slub-dependent, so I'm now
    > >>> working on the consistency of the other allocators regarding this name
    > >>> string duplicating thing.
    > >>
    > >> If you really need to kfree the string, or even if it is easier for you
    > >> this way, it can be done. As a matter of fact, this is the case for me.
    > >> Just that your patch is not enough. Christoph has a patch that makes
    > >> this behavior consistent over all allocators.
    > >
    > > Sorry, I didn't know that. Seems I don't need to continue the half-done
    > > work in slab. If possible, would you please give me a link of the patch?
    > > Thank you.
    > >
    >
    > Sorry for the delay. In case you haven't found it out yourself yet:
    >
    > http://www.spinics.net/lists/linux-mm/msg36149.html

    Thank you. I think it is better to have these things in the
    slab_common.c.

    >
    > Please not this posted patch as is has a bug.
    >
    > I do believe that your take on the aliasing code adds value to it. But
    > as I've already said once, might have to dig a bit deeper in that to get
    > to end of the rabbit hole.

    With slab_common, I think my slab/slob modifications are not needed any
    more. After I understand the common patches, I will check whether the
    aliasing problem in slub still exists, and if yes, try to send a patch
    based on that.



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