linux-kernel - Re: [PATCH v2 3/3] mm: cma: release trigger

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Date:	Wed, 28 Jan 2015 10:35:52 +0900
From:	Joonsoo Kim <js1304@...il.com>
To:	Sasha Levin <sasha.levin@...cle.com>
Cc:	Joonsoo Kim <iamjoonsoo.kim@....com>,
	LKML <linux-kernel@...r.kernel.org>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Laura Abbott <lauraa@...eaurora.org>
Subject: Re: [PATCH v2 3/3] mm: cma: release trigger

2015-01-28 5:13 GMT+09:00 Sasha Levin <sasha.levin@...cle.com>:
> On 01/27/2015 01:25 PM, Sasha Levin wrote:
>> On 01/27/2015 03:10 AM, Joonsoo Kim wrote:
>>>> >> +                if (mem->n <= count) {
>>>>> >> > +                     cma_release(cma, mem->p, mem->n);
>>>>> >> > +                     count -= mem->n;
>>>>> >> > +                     kfree(mem);
>>>>> >> > +             } else {
>>>>> >> > +                     cma_release(cma, mem->p, count);
>>>>> >> > +                     mem->p += count;
>>>>> >> > +                     mem->n -= count;
>>>>> >> > +                     count = 0;
>>>>> >> > +                     cma_add_to_cma_mem_list(mem);
>>>>> >> > +             }
>>>>> >> > +     }
>>> > If order_per_bit is not 0 and count used in cma_release() is
>>> > different with the count used in cma_alloc(), problem could
>>> > occur since bitmap management code can't handle that situation.
>>> >
>>> > Could we just disable this case in this testing module?
>> How should it behave then? Just free a max of 'count' pages and
>> stop beforehand if we're going to go over it?
>
> Actually, Can I just check for order_per_bit == 0 and execute it
> then? I don't want to avoid testing these paths.

Okay. I'm okay if you check order_per_bit == 0 in such case.

Thanks.
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