On Mon 18-05-20 19:40:55, Naresh Kamboju wrote:

Thanks for looking into this problem.

On Sat, 2 May 2020 at 02:28, Andrew Morton [off-list ref] wrote:

quoted

On Fri, 1 May 2020 18:08:28 +0530 Naresh Kamboju [off-list ref] wrote:

quoted

mkfs -t ext4 invoked oom-killer on i386 kernel running on x86_64 device
and started happening on linux -next master branch kernel tag next-20200430
and next-20200501. We did not bisect this problem.

[...]

Creating journal (131072 blocks): [   31.251333] mkfs.ext4 invoked
oom-killer: gfp_mask=0x101cc0(GFP_USER|__GFP_WRITE), order=0,
oom_score_adj=0

[...]

[   31.500943] DMA free:187396kB min:22528kB low:28160kB high:33792kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:4736kB inactive_file:431688kB unevictable:0kB
writepending:62020kB present:783360kB managed:668264kB mlocked:0kB
kernel_stack:888kB pagetables:0kB bounce:0kB free_pcp:880kB
local_pcp:216kB free_cma:163840kB

This is really unexpected. You are saying this is a regular i386 and DMA
should be bottom 16MB while yours is 780MB and the rest of the low mem
is in the Normal zone which is completely missing here. How have you got
to that configuration? I have to say I haven't seen anything like that
on i386.

The failing request is GFP_USER so highmem is not really allowed but
free pages are way above watermarks so the allocation should have just
succeeded.

-- 
Michal Hocko
SUSE Labs