[Devel] Re: [PATCH v5 04/18] slab: don't preemptively remove element from list in cache destroy

[Glauber Costa]

On 10/24/2012 10:54 AM, Pekka Enberg wrote:
> On Mon, Oct 22, 2012 at 11:40 AM, Glauber Costa <glommer at parallels.com> wrote:
>> On 10/19/2012 11:34 PM, Christoph Lameter wrote:
>>> On Fri, 19 Oct 2012, Glauber Costa wrote:
>>>
>>>> I, however, see no reason why we need to do so, since we are now locked
>>>> during the whole deletion (which wasn't necessarily true before).  I
>>>> propose a simplification in which we delete it only when there is no
>>>> more going back, so we don't need to add it again.
>>>
>>> Ok lets hope that holding the lock does not cause issues.
>>>
>>> Acked-by: Christoph Lameter <cl at linux.com>
>>>
>> BTW: One of the good things about this set, is that we are naturally
>> exercising cache destruction a lot more than we did before. So if there
>> is any problem, either with this or anything related to cache
>> destruction, it should at least show up a lot more frequently. So far,
>> this does not seem to cause any problems.
> 
> We no longer hold the mutex the whole time after. See commit 210ed9d
> ("mm, slab: release slab_mutex earlier in kmem_cache_destroy()") for
> details.
> 
I will resubmit then.

It doesn't really change the spirit of the patch. I took a look at that
fix, and what it does, is it releases the mutex right after
kmem_cache_shutdown() succeeds. Removing from the list in there would do
the trick.