Subject: Re: next-20160401+: ARM: DRA7: linux-next regression: mm/slab: clean-up kmem_cache_node setup

From: Jon Hunter <[email-masked]>
Date: Wed, 20 Apr 2016 08:11:41 +0100

Hi Joonsoo,

On 11/04/16 12:44, Jon Hunter wrote:
> On 11/04/16 03:02, Joonsoo Kim wrote:
>> On Fri, Apr 08, 2016 at 03:39:20PM -0500, Nishanth Menon wrote:
>>> Hi,
>>>
>>> http://marc.info/?l=linux-omap&m=146014314115625&w=2 series works with
>>> v4.6-rc2 kernel, however, it fails with linux-next for suspend-to-ram
>>> (mem) on BeagleBoard-X15
>>>
>>> next-20160327 - good
>>> next-20160329 - good
>>> next-20160330 - Fails to boot - I2C crashes
>>> next-20160331-  Fails to boot - USB crashes
>>> next-20160401 -> bad
>>> next-20160408 -> bad
>>>
>>> Bisect log of next-20160408 vs v4.6-rc2 ->
>>> http://pastebin.ubuntu.com/15697856/
>>>
>>> # first bad commit: [2b629704a2b6a5b239f23750e5517a9d8c3a4e8c]
>>> mm/slab: clean-up kmem_cache_node setup
>>>
>>
>> Hello,
>>
>> I made a mistake on that patch. Could you try to test below one on
>> top of it.
>>
>> Thanks.
>>
>> --------->8----------------
>> From d3af3cc409527e9be6beb62ea395cde67f3c5029 Mon Sep 17 00:00:00 2001
>> From: Joonsoo Kim <[email-masked]>
>> Date: Mon, 11 Apr 2016 10:48:29 +0900
>> Subject: [PATCH] mm/slab: clean-up kmem_cache_node setup-fix
>>
>> After calling free_block(), we need to re-calculate array_cache's
>> avail counter. Fix it.
>>
>> And, it's better to free objects in shared array when it is
>> really necessary. Check it before calling free_block().
>>
>> Signed-off-by: Joonsoo Kim <[email-masked]>
>> ---
>>  mm/slab.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/slab.c b/mm/slab.c
>> index fcd5fbb..27cb390 100644
>> --- a/mm/slab.c
>> +++ b/mm/slab.c
>> @@ -927,9 +927,10 @@ static int setup_kmem_cache_node(struct kmem_cache *cachep,
>>  
>>  	n = get_node(cachep, node);
>>  	spin_lock_irq(&n->list_lock);
>> -	if (n->shared) {
>> +	if (n->shared && force_change) {
>>  		free_block(cachep, n->shared->entry,
>>  				n->shared->avail, node, &list);
>> +		n->shared->avail = 0;
>>  	}
>>  
>>  	if (!n->shared || force_change) {
> 
> This also fixes a regression on -next for Tegra that was bisected down
> to the same culprit. So ...
> 
> Tested-by: Jon Hunter <[email-masked]>

This fix still doesn't appear to have made it into -next and this has
been broken now for nearly 3 weeks. Any chance we can get this into -next?

Cheers
Jon