Re: mm: mkfs.ext4 invoked oom-killer on i386 - pagecache_get_page

[Arnd Bergmann]

On Tue, May 19, 2020 at 9:52 AM Michal Hocko <mhocko@xxxxxxxxxx> wrote:
>
> 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 <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > On Fri, 1 May 2020 18:08:28 +0530 Naresh Kamboju <naresh.kamboju@xxxxxxxxxx> wrote:
> > >
> > > > 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.

I think that line comes from an ARM32 beaglebone-X15 machine showing
the same symptom. The i386 line from the log file that Naresh linked to at
https://lkft.validation.linaro.org/scheduler/job/1406110#L1223  is less
unusual:

[   34.931663] Node 0 active_anon:21464kB inactive_anon:8688kB
active_file:16604kB inactive_file:849976kB unevictable:0kB
isolated(anon):0kB isolated(file):0kB mapped:25284kB dirty:58952kB
writeback:27772kB shmem:8944kB writeback_tmp:0kB unstable:0kB
all_unreclaimable? yes
[   34.955523] DMA free:3356kB min:68kB low:84kB high:100kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:11964kB unevictable:0kB
writepending:11980kB present:15964kB managed:15876kB mlocked:0kB
kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB
free_cma:0kB
[   34.983385] lowmem_reserve[]: 0 825 1947 825
[   34.987678] Normal free:3948kB min:7732kB low:8640kB high:9548kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:1096kB inactive_file:786400kB unevictable:0kB
writepending:65432kB present:884728kB managed:845576kB mlocked:0kB
kernel_stack:1112kB pagetables:0kB bounce:0kB free_pcp:2908kB
local_pcp:500kB free_cma:0kB
[   35.017427] lowmem_reserve[]: 0 0 8980 0
[   35.021362] HighMem free:1049496kB min:512kB low:1748kB high:2984kB
reserved_highatomic:0KB active_anon:21464kB inactive_anon:8688kB
active_file:15508kB inactive_file:51612kB unevictable:0kB
writepending:0kB present:1149540kB managed:1149540kB mlocked:0kB
kernel_stack:0kB pagetables:712kB bounce:0kB free_pcp:1524kB
local_pcp:292kB free_cma:0kB
[   35.051717] lowmem_reserve[]: 0 0 0 0
[   35.055374] DMA: 8*4kB (UE) 1*8kB (E) 1*16kB (E) 0*32kB 0*64kB
0*128kB 1*256kB (E) 0*512kB 1*1024kB (E) 1*2048kB (E) 0*4096kB =
3384kB
[   35.067446] Normal: 27*4kB (U) 23*8kB (U) 12*16kB (UE) 12*32kB (U)
4*64kB (UE) 2*128kB (U) 2*256kB (UE) 1*512kB (E) 0*1024kB 1*2048kB (U)
0*4096kB = 4452kB
[   35.081347] HighMem: 2*4kB (UM) 0*8kB 1*16kB (M) 2*32kB (UM) 1*64kB
(U) 0*128kB 1*256kB (M) 1*512kB (M) 0*1024kB 0*2048kB 256*4096kB (M) =
1049496kB

        Arnd