Explanation for "Killed Process"

The system has killed a process due to "Out of memory" but I cannot understand these messages.
I am not able to find the memory issue.

[Mon Jul 20 21:20:39 2020] crawler invoked oom-killer: gfp_mask=0x24201ca, order=0, oom_score_adj=0
[Mon Jul 20 21:20:39 2020] crawler cpuset=/ mems_allowed=0
[Mon Jul 20 21:20:39 2020] CPU: 0 PID: 24357 Comm: crawler Not tainted 4.4.0-1098-aws #109-Ubuntu
[Mon Jul 20 21:20:39 2020] Hardware name: Xen HVM domU, BIOS 4.2.amazon 08/24/2006
[Mon Jul 20 21:20:39 2020]  0000000000000286 1f6ee74fe469971b ffff8800978779e0 ffffffff81408801
[Mon Jul 20 21:20:39 2020]  ffff880097877b98 ffff880204a5ee00 ffff880097877a50 ffffffff81216217
[Mon Jul 20 21:20:39 2020]  0000000000000000 ffff8800e2e2e9c0 ffff8801148cc4c0 ffff880097877a38
[Mon Jul 20 21:20:39 2020] Call Trace:
[Mon Jul 20 21:20:39 2020]  [<ffffffff81408801>] dump_stack+0x63/0x82
[Mon Jul 20 21:20:39 2020]  [<ffffffff81216217>] dump_header+0x5a/0x1c3
[Mon Jul 20 21:20:39 2020]  [<ffffffff813a04e1>] ? apparmor_capable+0x131/0x1b0
[Mon Jul 20 21:20:39 2020]  [<ffffffff8119a94b>] oom_kill_process+0x20b/0x3d0
[Mon Jul 20 21:20:39 2020]  [<ffffffff8119ad58>] out_of_memory+0x1f8/0x460
[Mon Jul 20 21:20:39 2020]  [<ffffffff811a0db3>] __alloc_pages_slowpath.constprop.89+0x943/0xaf0
[Mon Jul 20 21:20:39 2020]  [<ffffffff811a11ff>] __alloc_pages_nodemask+0x29f/0x2b0
[Mon Jul 20 21:20:39 2020]  [<ffffffff811ec7cc>] alloc_pages_current+0x8c/0x110
[Mon Jul 20 21:20:39 2020]  [<ffffffff81196a8b>] __page_cache_alloc+0xab/0xc0
[Mon Jul 20 21:20:39 2020]  [<ffffffff811993b0>] filemap_fault+0x160/0x440
[Mon Jul 20 21:20:39 2020]  [<ffffffff812af5c6>] ext4_filemap_fault+0x36/0x50
[Mon Jul 20 21:20:39 2020]  [<ffffffff811c6b87>] __do_fault+0x77/0x110
[Mon Jul 20 21:20:39 2020]  [<ffffffff811cab29>] handle_mm_fault+0x1259/0x1b80
[Mon Jul 20 21:20:39 2020]  [<ffffffff8183ee61>] ? __schedule+0x301/0x810
[Mon Jul 20 21:20:39 2020]  [<ffffffff8183ee6d>] ? __schedule+0x30d/0x810
[Mon Jul 20 21:20:39 2020]  [<ffffffff8183ee61>] ? __schedule+0x301/0x810
[Mon Jul 20 21:20:39 2020]  [<ffffffff8183ee6d>] ? __schedule+0x30d/0x810
[Mon Jul 20 21:20:39 2020]  [<ffffffff8183ee61>] ? __schedule+0x301/0x810
[Mon Jul 20 21:20:39 2020]  [<ffffffff8106de74>] __do_page_fault+0x1a4/0x410
[Mon Jul 20 21:20:39 2020]  [<ffffffff810fa96c>] ? ktime_get_ts64+0x4c/0x100
[Mon Jul 20 21:20:39 2020]  [<ffffffff8106e102>] do_page_fault+0x22/0x30
[Mon Jul 20 21:20:39 2020]  [<ffffffff81846938>] page_fault+0x28/0x30
[Mon Jul 20 21:20:39 2020] Mem-Info:
[Mon Jul 20 21:20:39 2020] active_anon:1971173 inactive_anon:13648 isolated_anon:0
                            active_file:0 inactive_file:21 isolated_file:0
                            unevictable:913 dirty:0 writeback:0 unstable:0
                            slab_reclaimable:7341 slab_unreclaimable:9130
                            mapped:1013 shmem:20671 pagetables:5035 bounce:0
                            free:25558 free_pcp:31 free_cma:0
[Mon Jul 20 21:20:39 2020] Node 0 DMA free:15900kB min:128kB low:160kB high:192kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15988kB managed:15900kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
[Mon Jul 20 21:20:39 2020] lowmem_reserve[]: 0 3729 7951 7951 7951
[Mon Jul 20 21:20:39 2020] Node 0 DMA32 free:48524kB min:31640kB low:39548kB high:47460kB active_anon:3694868kB inactive_anon:31728kB active_file:28kB inactive_file:56kB unevictable:1984kB isolated(anon):0kB isolated(file):0kB present:3915776kB managed:3835212kB mlocked:1984kB dirty:0kB writeback:0kB mapped:2068kB shmem:40836kB slab_reclaimable:11392kB slab_unreclaimable:17676kB kernel_stack:1488kB pagetables:9948kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:552 all_unreclaimable? yes
[Mon Jul 20 21:20:39 2020] lowmem_reserve[]: 0 0 4221 4221 4221
[Mon Jul 20 21:20:39 2020] Node 0 Normal free:37808kB min:35808kB low:44760kB high:53712kB active_anon:4189824kB inactive_anon:22864kB active_file:0kB inactive_file:28kB unevictable:1668kB isolated(anon):0kB isolated(file):0kB present:4456448kB managed:4322624kB mlocked:1668kB dirty:0kB writeback:0kB mapped:1984kB shmem:41848kB slab_reclaimable:17972kB slab_unreclaimable:18844kB kernel_stack:1440kB pagetables:10192kB unstable:0kB bounce:0kB free_pcp:124kB local_pcp:4kB free_cma:0kB writeback_tmp:0kB pages_scanned:212 all_unreclaimable? yes
[Mon Jul 20 21:20:39 2020] lowmem_reserve[]: 0 0 0 0 0
[Mon Jul 20 21:20:39 2020] Node 0 DMA: 1*4kB (U) 1*8kB (U) 1*16kB (U) 0*32kB 2*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15900kB
[Mon Jul 20 21:20:39 2020] Node 0 DMA32: 358*4kB (UME) 132*8kB (UME) 281*16kB (UME) 128*32kB (UME) 98*64kB (UME) 30*128kB (UME) 23*256kB (E) 14*512kB (ME) 8*1024kB (E) 3*2048kB (E) 0*4096kB = 48584kB
[Mon Jul 20 21:20:39 2020] Node 0 Normal: 423*4kB (UME) 127*8kB (UE) 153*16kB (UME) 172*32kB (UE) 103*64kB (UE) 39*128kB (UE) 21*256kB (UE) 10*512kB (ME) 1*1024kB (E) 0*2048kB 1*4096kB (H) = 37860kB
[Mon Jul 20 21:20:39 2020] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[Mon Jul 20 21:20:39 2020] 21375 total pagecache pages
[Mon Jul 20 21:20:39 2020] 0 pages in swap cache
[Mon Jul 20 21:20:39 2020] Swap cache stats: add 0, delete 0, find 0/0
[Mon Jul 20 21:20:39 2020] Free swap  = 0kB
[Mon Jul 20 21:20:39 2020] Total swap = 0kB
[Mon Jul 20 21:20:39 2020] 2097053 pages RAM
[Mon Jul 20 21:20:39 2020] 0 pages HighMem/MovableOnly
[Mon Jul 20 21:20:39 2020] 53619 pages reserved
[Mon Jul 20 21:20:39 2020] 0 pages cma reserved
[Mon Jul 20 21:20:39 2020] 0 pages hwpoisoned
[Mon Jul 20 21:20:39 2020] Out of memory: Kill process 24355 (crawler) score 957 or sacrifice child
[Mon Jul 20 21:20:39 2020] Killed process 24355 (crawler) total-vm:9099416kB, anon-rss:7805456kB, file-rss:0kB

Regards
Thanks in advance