Re: [dummy_stm_init] swapper/0: page allocation failure: order:9, mode:0x14040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)

[Alexander Shishkin]

On Thu, Apr 19, 2018 at 08:51:11AM +0200, Michal Hocko wrote:
> On Thu 19-04-18 10:36:39, Wu Fengguang wrote:
> > Hi Alexander,
> > 
> > FYI this happens in mainline kernel 4.17.0-rc1.
> > It dates back to at least v4.15.
> > 
> > It occurs in 4 out of 4 boots. Here KVM has 1G memory.
> > 
> > This high order allocation caused lots of noises in our boot testing.
> > We could disable this device in our tests, but it would be great if
> > there are better ways out.
> > 
> > [   75.039408]       Product name: fake-design-for-testing
> > [   75.040995] fmc fake-design-for-testing-f001: Driver has no ID: matches all
> > [   75.042509] fmc_trivial: probe of fake-design-for-testing-f001 failed with error -95
> > [   75.044323] fmc fake-design-for-testing-f001: Driver has no ID: matches all
> > [   75.045644] fmc_chardev fake-design-for-testing-f001: Created misc device "fake-design-for-testing-f001"
> > [   75.061570] swapper/0: page allocation failure: order:9, mode:0x14040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
> 
> Is there any reason why
> > [   75.063338]  stm_register_device+0xf3/0x5c0:
> > 						stm_register_device at drivers/hwtracing/stm/core.c:695
> 
> cannot use kvzalloc?

You're right, of course, I'll fix that.
I can't see, though, how it ends up asking order==9 from the buddy
allocator. The kmalloc() in question should be asking for ~512kB,
theres should be smaller slabs for that.

Regards,
--
Alex