Re: [RESEND PATCH V2] mm: page_alloc: unreserve highatomic page blocks before oom

[gregkh@xxxxxxxxxxxxxxxxxxx]

On Tue, Jan 23, 2024 at 12:24:22PM +0100, Michal Hocko wrote:
> On Tue 23-01-24 11:08:28, Joakim Tjernlund wrote:
> [...]
> > Mar  9 12:52:40 xr kern.warn kernel: [ 1066.001379] Mem-Info:
> > Mar  9 12:52:40 xr kern.warn kernel: [ 1066.003665] active_anon:18 inactive_anon:2435 isolated_anon:0
> > Mar  9 12:52:40 xr kern.warn kernel: [ 1066.003665]  active_file:1 inactive_file:0 isolated_file:0
> > Mar  9 12:52:40 xr kern.warn kernel: [ 1066.003665]  unevictable:267 dirty:0 writeback:0
> > Mar  9 12:52:40 xr kern.warn kernel: [ 1066.003665]  slab_reclaimable:384 slab_unreclaimable:2223
> > Mar  9 12:52:40 xr kern.warn kernel: [ 1066.003665]  mapped:1 shmem:0 pagetables:309 bounce:0
> > Mar  9 12:52:41 xr kern.warn kernel: [ 1066.003665]  kernel_misc_reclaimable:0
> > Mar  9 12:52:41 xr kern.warn kernel: [ 1066.003665]  free:1054 free_pcp:24 free_cma:0
> > Mar  9 12:52:41 xr kern.warn kernel: [ 1066.037938] Node 0 active_anon:72kB inactive_anon:9740kB active_file:4kB inactive_file:0kB unevictable:1068kB isolated(anon):0kB isolated(file):0kB mapped:4kB dirty:0kB writeback:0kB shmem:0kB writeback_tmp:0kB kernel_stack:9
> > Mar  9 12:52:41 xr kern.warn kernel: [ 1066.061723] Normal free:4216kB min:128kB low:160kB high:192kB reserved_highatomic:4096KB active_anon:72kB inactive_anon:9740kB active_file:4kB inactive_file:0kB unevictable:1068kB writepending:0kB present:36864kB managed:2944
> > Mar  9 12:52:41 xr kern.warn kernel: [ 1066.087595] lowmem_reserve[]: 0 0
> > Mar  9 12:52:41 xr kern.warn kernel: [ 1066.090918] Normal: 206*4kB (MEH) 198*8kB (UMEH) 79*16kB (UMEH) 13*32kB (H) 2*64kB (H) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 4216kB
> > Mar  9 12:52:41 xr kern.warn kernel: [ 1066.104104] 269 total pagecache pages
> > Mar  9 12:52:41 xr kern.warn kernel: [ 1066.107768] 9216 pages RAM
> 
> OK, so this is really a tiny system (36MB) and having 4MB in highatomic
> reserves is clearly too much. So this matches the patch you are
> referencing and it migh help you indeed.

Ok, now queued up, thanks.

greg k-h