From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Rabin Vincent <rabin@rab.in>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: CMA and zone watermarks
Date: Tue, 09 Oct 2012 07:16:21 +0200 [thread overview]
Message-ID: <5073B325.6060905@samsung.com> (raw)
In-Reply-To: <20121009050748.GH13817@bbox>
Hello,
On 10/9/2012 7:07 AM, Minchan Kim wrote:
> On Tue, Oct 09, 2012 at 06:53:29AM +0200, Marek Szyprowski wrote:
>> Hello,
>>
>> On 10/9/2012 6:43 AM, Minchan Kim wrote:
>>> On Tue, Oct 09, 2012 at 05:12:21AM +0200, Marek Szyprowski wrote:
>>>> On 10/9/2012 5:10 AM, Minchan Kim wrote:
>>>>> On Mon, Oct 08, 2012 at 05:41:14PM +0200, Rabin Vincent wrote:
>>
>>>>> Fortunately, recently, Bart sent a patch about that.
>>>>> http://marc.info/?l=linux-mm&m=134763299016693&w=2
>>>>>
>>>>> Could you test above patches in your kernel?
>>>>> You have to apply [2/4], [3/4], [4/4] and don't need [1/4].
>>>>
>>>> AFAIR without patch [1/4], free cma page counter will go below zero
>>>> and weird thing will happen, so better apply the complete patchset.
>>>
>>> I can't understand your point. [1/4] is just fix for correcting trace
>>> No?
>>
>> I just remember we ran into such strange negative number of free cma
>> pages issue without that patch, but maybe the final patchset will
>> simply fail to apply without the first patch.
>
> I have no objection to apply them all, of course.
> But note that if you suffer from such strange bug without [1/4],
> it should be dug in without buring into just "fixing of the trace"
> comment. As I saw the code without [1/4], I can't find any fault.
> Could you elaborate it more if you have any guessing in mind?
I remember that in one version of the Bartek's patches,
page_private(page) has been used directly for getting the migratetype
after a call to __free_one_page() (the same way as
trace_mm_page_pcpu_drain() used it), what resulted in incorrect counting
of free pages. The issue has been fixed then by the patch [1/4].
Now I've check that the next patches use mt variable instead of
page_private(page), so they will simply not apply without [1/4]. No
other issues should be expected. I'm sorry for confusion.
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
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WARNING: multiple messages have this Message-ID (diff)
From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Rabin Vincent <rabin@rab.in>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: CMA and zone watermarks
Date: Tue, 09 Oct 2012 07:16:21 +0200 [thread overview]
Message-ID: <5073B325.6060905@samsung.com> (raw)
In-Reply-To: <20121009050748.GH13817@bbox>
Hello,
On 10/9/2012 7:07 AM, Minchan Kim wrote:
> On Tue, Oct 09, 2012 at 06:53:29AM +0200, Marek Szyprowski wrote:
>> Hello,
>>
>> On 10/9/2012 6:43 AM, Minchan Kim wrote:
>>> On Tue, Oct 09, 2012 at 05:12:21AM +0200, Marek Szyprowski wrote:
>>>> On 10/9/2012 5:10 AM, Minchan Kim wrote:
>>>>> On Mon, Oct 08, 2012 at 05:41:14PM +0200, Rabin Vincent wrote:
>>
>>>>> Fortunately, recently, Bart sent a patch about that.
>>>>> http://marc.info/?l=linux-mm&m=134763299016693&w=2
>>>>>
>>>>> Could you test above patches in your kernel?
>>>>> You have to apply [2/4], [3/4], [4/4] and don't need [1/4].
>>>>
>>>> AFAIR without patch [1/4], free cma page counter will go below zero
>>>> and weird thing will happen, so better apply the complete patchset.
>>>
>>> I can't understand your point. [1/4] is just fix for correcting trace
>>> No?
>>
>> I just remember we ran into such strange negative number of free cma
>> pages issue without that patch, but maybe the final patchset will
>> simply fail to apply without the first patch.
>
> I have no objection to apply them all, of course.
> But note that if you suffer from such strange bug without [1/4],
> it should be dug in without buring into just "fixing of the trace"
> comment. As I saw the code without [1/4], I can't find any fault.
> Could you elaborate it more if you have any guessing in mind?
I remember that in one version of the Bartek's patches,
page_private(page) has been used directly for getting the migratetype
after a call to __free_one_page() (the same way as
trace_mm_page_pcpu_drain() used it), what resulted in incorrect counting
of free pages. The issue has been fixed then by the patch [1/4].
Now I've check that the next patches use mt variable instead of
page_private(page), so they will simply not apply without [1/4]. No
other issues should be expected. I'm sorry for confusion.
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
next prev parent reply other threads:[~2012-10-09 5:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-08 15:41 CMA and zone watermarks Rabin Vincent
2012-10-09 0:37 ` Marek Szyprowski
2012-10-09 0:37 ` Marek Szyprowski
2012-10-09 15:25 ` Rabin Vincent
2012-10-09 15:25 ` Rabin Vincent
2012-10-09 3:10 ` Minchan Kim
2012-10-09 3:10 ` Minchan Kim
2012-10-09 3:12 ` Marek Szyprowski
2012-10-09 3:12 ` Marek Szyprowski
2012-10-09 4:43 ` Minchan Kim
2012-10-09 4:43 ` Minchan Kim
2012-10-09 4:53 ` Marek Szyprowski
2012-10-09 4:53 ` Marek Szyprowski
2012-10-09 5:07 ` Minchan Kim
2012-10-09 5:07 ` Minchan Kim
2012-10-09 5:16 ` Marek Szyprowski [this message]
2012-10-09 5:16 ` Marek Szyprowski
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