Re: Linux 3.19-rc3

Steve Capper
2015-01-09T14:19:55Z

On 9 January 2015 at 12:13, Mark Rutland <mark.rutland@arm.com> wrote:
> On Thu, Jan 08, 2015 at 12:51:31PM +0000, Mark Langsdorf wrote:
>> On 01/05/2015 07:46 PM, Linus Torvalds wrote:
>> > It's a day delayed - not because of any particular development issues,
>> > but simply because I was tiling a bathroom yesterday. But rc3 is out
>> > there now, and things have stayed reasonably calm. I really hope that
>> > implies that 3.19 is looking good, but it's equally likely that it's
>> > just that people are still recovering from the holiday season.
>>
>> I'm consistently getting an out of memory killer triggered when
>> compiling the kernel (make -j 16 -s) on a 16 core ARM64 system
>> with 16 GB of memory. This doesn't happen when running a 3.18
>> kernel.
>>
>> I'm going to start bisecting the failure now, but here's the crash
>> log in case someone can see something obvious in it.
>
> FWIW I've just reproduced this with v3.19-rc3 defconfig +
> CONFIG_ARM64_64K_PAGES=y by attempting a git clone of mainline. My
> system has 16GB of RAM and 6 CPUs.
>
> I have a similarly dodgy looking number of pages reserved
> (18446744073709544451 A.K.A. -7165). Log below.
>

I think the negative page reserved count is a consequence of another bug.

We have the following reporting code in lib/show_mem.c:
#ifdef CONFIG_CMA
printk("%lu pages reserved\n", (reserved - totalcma_pages));
printk("%lu pages cma reserved\n", totalcma_pages);
#else

With totalcma_pages being reported as 8192, that would account for the
-7000ish values reported.

That change appears to have come from:
49abd8c lib/show_mem.c: add cma reserved information

Is the quickest way to exacerbate this OOM a kernel compile?

Cheers,
--
Steve