Great How-To, but it seems that it has some memory leak, this is what happened after lots of requests: (15k?) (this is my entire kernel log from luci)
Well, for some time I will keep it disabled.
[14074.160000] ath: skbuff alloc of size 1926 failed
[14074.160000] dnscrypt-proxy: page allocation failure: order:0, mode:0x4020
[14074.160000] Call Trace:[<802663e8>] 0x802663e8
[14074.160000] [<802663e8>] 0x802663e8
[14074.160000] [<800ad368>] 0x800ad368
[14074.160000] [<800af668>] 0x800af668
[14074.160000] [<802d0000>] 0x802d0000
[14074.160000] [<800d2e60>] 0x800d2e60
[14074.160000] [<80071ca4>] 0x80071ca4
[14074.160000] [<80267834>] 0x80267834
[14074.160000] [<800721e0>] 0x800721e0
[14074.160000] [<800d4838>] 0x800d4838
[14074.160000] [<801d6c44>] 0x801d6c44
[14074.160000] [<814bc0c0>] 0x814bc0c0
[14074.160000] [<801d6be8>] 0x801d6be8
[14074.160000] [<814bc0c0>] 0x814bc0c0
[14074.160000] [<81fa6d4c>] 0x81fa6d4c
[14074.160000] [<8008e064>] 0x8008e064
[14074.160000] [<8009659c>] 0x8009659c
[14074.160000] [<81fa4318>] 0x81fa4318
[14074.160000] [<80076300>] 0x80076300
[14074.160000] [<80076824>] 0x80076824
[14074.160000] [<80076a30>] 0x80076a30
[14074.160000] [<80089360>] 0x80089360
[14074.160000] [<80076c64>] 0x80076c64
[14074.160000] [<80062d2c>] 0x80062d2c
[14074.160000]
[14074.160000] Mem-Info:
[14074.160000] Normal per-cpu:
[14074.160000] CPU 0: hi: 0, btch: 1 usd: 0
[14074.160000] active_anon:614 inactive_anon:18 isolated_anon:0
[14074.160000] active_file:1164 inactive_file:1399 isolated_file:0
[14074.160000] unevictable:0 dirty:0 writeback:0 unstable:0
[14074.160000] free:68 slab_reclaimable:371 slab_unreclaimable:2725
[14074.160000] mapped:473 shmem:56 pagetables:85 bounce:0
[14074.160000] Normal free:272kB min:720kB low:900kB high:1080kB active_anon:2456kB inactive_anon:72kB active_file:4656kB inactive_file:5596kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:32512kB mlocked:0kB dirty:0kB writeback:0kB mapped:1892kB shmem:224kB slab_reclaimable:1484kB slab_unreclaimable:10900kB kernel_stack:368kB pagetables:340kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[14074.160000] lowmem_reserve[]: 0 0
[14074.160000] Normal: 54*4kB 1*8kB 1*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 272kB
[14074.160000] 2619 total pagecache pages
[14074.160000] 0 pages in swap cache
[14074.160000] Swap cache stats: add 0, delete 0, find 0/0
[14074.160000] Free swap = 0kB
[14074.160000] Total swap = 0kB
[14074.160000] 8192 pages RAM
[14074.160000] 820 pages reserved
[14074.160000] 2465 pages shared
[14074.160000] 6165 pages non-shared
[14074.160000] SLUB: Unable to allocate memory on node -1 (gfp=0x20)
[14074.160000] cache: kmalloc-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
[14074.160000] node 0: slabs: 0, objs: 0, free: 0
[14074.390000] ath: skbuff alloc of size 1926 failed
[14074.400000] dnscrypt-proxy: page allocation failure: order:0, mode:0x4020
[14074.400000] Call Trace:[<802663e8>] 0x802663e8
[14074.400000] [<802663e8>] 0x802663e8
[14074.400000] [<800ad368>] 0x800ad368
[14074.400000] [<800af668>] 0x800af668
[14074.400000] [<80194714>] 0x80194714
[14074.400000] [<802d0000>] 0x802d0000
[14074.400000] [<800d2e60>] 0x800d2e60
[14074.400000] [<80267834>] 0x80267834
[14074.400000] [<800721e0>] 0x800721e0
[14074.400000] [<80072200>] 0x80072200
[14074.400000] [<800d4838>] 0x800d4838
[14074.400000] [<801d6c44>] 0x801d6c44
[14074.400000] [<814bc0c0>] 0x814bc0c0
[14074.400000] [<801d6be8>] 0x801d6be8
[14074.400000] [<814bc0c0>] 0x814bc0c0
[14074.400000] [<81fa6d4c>] 0x81fa6d4c
[14074.400000] [<8008e064>] 0x8008e064
[14074.400000] [<8009659c>] 0x8009659c
[14074.400000] [<81fa4318>] 0x81fa4318
[14074.400000] [<80076300>] 0x80076300
[14074.400000] [<80076824>] 0x80076824
[14074.400000] [<80076a30>] 0x80076a30
[14074.400000] [<80089360>] 0x80089360
[14074.400000] [<80076c64>] 0x80076c64
[14074.400000] [<80062d2c>] 0x80062d2c
[14074.400000]
[14074.400000] Mem-Info:
[14074.400000] Normal per-cpu:
[14074.400000] CPU 0: hi: 0, btch: 1 usd: 0
[14074.400000] active_anon:614 inactive_anon:18 isolated_anon:0
[14074.400000] active_file:1164 inactive_file:1399 isolated_file:0
[14074.400000] unevictable:0 dirty:0 writeback:0 unstable:0
[14074.400000] free:68 slab_reclaimable:371 slab_unreclaimable:2725
[14074.400000] mapped:473 shmem:56 pagetables:85 bounce:0
[14074.400000] Normal free:272kB min:720kB low:900kB high:1080kB active_anon:2456kB inactive_anon:72kB active_file:4656kB inactive_file:5596kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:32512kB mlocked:0kB dirty:0kB writeback:0kB mapped:1892kB shmem:224kB slab_reclaimable:1484kB slab_unreclaimable:10900kB kernel_stack:368kB pagetables:340kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[14074.400000] lowmem_reserve[]: 0 0
[14074.400000] Normal: 54*4kB 1*8kB 1*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 272kB
[14074.400000] 2619 total pagecache pages
[14074.400000] 0 pages in swap cache
[14074.400000] Swap cache stats: add 0, delete 0, find 0/0
[14074.400000] Free swap = 0kB
[14074.400000] Total swap = 0kB
[14074.400000] 8192 pages RAM
[14074.400000] 820 pages reserved
[14074.400000] 2465 pages shared
[14074.400000] 6165 pages non-shared
[14074.400000] SLUB: Unable to allocate memory on node -1 (gfp=0x20)
[14074.400000] cache: kmalloc-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
[14074.400000] node 0: slabs: 0, objs: 0, free: 0
[14074.640000] ath: skbuff alloc of size 1926 failed
[14074.640000] dnscrypt-proxy: page allocation failure: order:0, mode:0x4020
[14074.640000] Call Trace:[<802663e8>] 0x802663e8
[14074.640000] [<802663e8>] 0x802663e8
[14074.640000] [<800ad368>] 0x800ad368
[14074.640000] [<800af668>] 0x800af668
[14074.640000] [<802d0000>] 0x802d0000
[14074.640000] [<800d2e60>] 0x800d2e60
[14074.640000] [<80071ca4>] 0x80071ca4
[14074.640000] [<80267834>] 0x80267834
[14074.640000] [<800721e0>] 0x800721e0
[14074.640000] [<800d4838>] 0x800d4838
[14074.640000] [<801d6c44>] 0x801d6c44
[14074.640000] [<814bc0c0>] 0x814bc0c0
[14074.640000] [<801d6be8>] 0x801d6be8
[14074.640000] [<814bc0c0>] 0x814bc0c0
[14074.640000] [<81fa6d4c>] 0x81fa6d4c
[14074.640000] [<8008e064>] 0x8008e064
[14074.640000] [<8009659c>] 0x8009659c
[14074.640000] [<81fa4318>] 0x81fa4318
[14074.640000] [<80076300>] 0x80076300
[14074.640000] [<80076824>] 0x80076824
[14074.640000] [<80076a30>] 0x80076a30
[14074.640000] [<80089360>] 0x80089360
[14074.640000] [<80076c64>] 0x80076c64
[14074.640000] [<80062d2c>] 0x80062d2c
[14074.640000]
[14074.640000] Mem-Info:
[14074.640000] Normal per-cpu:
[14074.640000] CPU 0: hi: 0, btch: 1 usd: 0
[14074.640000] active_anon:614 inactive_anon:18 isolated_anon:0
[14074.640000] active_file:1164 inactive_file:1399 isolated_file:0
[14074.640000] unevictable:0 dirty:0 writeback:0 unstable:0
[14074.640000] free:68 slab_reclaimable:371 slab_unreclaimable:2725
[14074.640000] mapped:473 shmem:56 pagetables:85 bounce:0
[14074.640000] Normal free:272kB min:720kB low:900kB high:1080kB active_anon:2456kB inactive_anon:72kB active_file:4656kB inactive_file:5596kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:32512kB mlocked:0kB dirty:0kB writeback:0kB mapped:1892kB shmem:224kB slab_reclaimable:1484kB slab_unreclaimable:10900kB kernel_stack:368kB pagetables:340kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[14074.640000] lowmem_reserve[]: 0 0
[14074.640000] Normal: 54*4kB 1*8kB 1*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 272kB
[14074.640000] 2619 total pagecache pages
[14074.640000] 0 pages in swap cache
[14074.640000] Swap cache stats: add 0, delete 0, find 0/0
[14074.640000] Free swap = 0kB
[14074.640000] Total swap = 0kB
[14074.640000] 8192 pages RAM
[14074.640000] 820 pages reserved
[14074.640000] 2465 pages shared
[14074.640000] 6165 pages non-shared
[14074.640000] SLUB: Unable to allocate memory on node -1 (gfp=0x20)
[14074.640000] cache: kmalloc-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
[14074.640000] node 0: slabs: 0, objs: 0, free: 0
[14074.880000] ath: skbuff alloc of size 1926 failed
[14074.880000] dnscrypt-proxy: page allocation failure: order:0, mode:0x4020
[14074.880000] Call Trace:[<802663e8>] 0x802663e8
[14074.880000] [<802663e8>] 0x802663e8
[14074.880000] [<800ad368>] 0x800ad368
[14074.880000] [<800af668>] 0x800af668
[14074.880000] [<802d0000>] 0x802d0000
[14074.880000] [<800d2e60>] 0x800d2e60
[14074.880000] [<80071ca4>] 0x80071ca4
[14074.880000] [<80267834>] 0x80267834
[14074.880000] [<800721e0>] 0x800721e0
[14074.880000] [<800d4838>] 0x800d4838
[14074.880000] [<801d6c44>] 0x801d6c44
[14074.880000] [<814bc0c0>] 0x814bc0c0
[14074.880000] [<801d6be8>] 0x801d6be8
[14074.880000] [<814bc0c0>] 0x814bc0c0
[14074.880000] [<81fa6d4c>] 0x81fa6d4c
[14074.880000] [<8008e064>] 0x8008e064
[14074.880000] [<8009659c>] 0x8009659c
[14074.880000] [<81fa4318>] 0x81fa4318
[14074.880000] [<80076300>] 0x80076300
[14074.880000] [<80076824>] 0x80076824
[14074.880000] [<80076a30>] 0x80076a30
[14074.880000] [<80089360>] 0x80089360
[14074.880000] [<80076c64>] 0x80076c64
[14074.880000] [<80062d2c>] 0x80062d2c
[14074.880000]
[14074.880000] Mem-Info:
[14074.880000] Normal per-cpu:
[14074.880000] CPU 0: hi: 0, btch: 1 usd: 0
[14074.880000] active_anon:614 inactive_anon:18 isolated_anon:0
[14074.880000] active_file:1164 inactive_file:1399 isolated_file:0
[14074.880000] unevictable:0 dirty:0 writeback:0 unstable:0
[14074.880000] free:68 slab_reclaimable:371 slab_unreclaimable:2725
[14074.880000] mapped:473 shmem:56 pagetables:85 bounce:0
[14074.880000] Normal free:272kB min:720kB low:900kB high:1080kB active_anon:2456kB inactive_anon:72kB active_file:4656kB inactive_file:5596kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:32512kB mlocked:0kB dirty:0kB writeback:0kB mapped:1892kB shmem:224kB slab_reclaimable:1484kB slab_unreclaimable:10900kB kernel_stack:368kB pagetables:340kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[14074.880000] lowmem_reserve[]: 0 0
[14074.880000] Normal: 54*4kB 1*8kB 1*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 272kB
[14074.880000] 2619 total pagecache pages
[14074.880000] 0 pages in swap cache
[14074.880000] Swap cache stats: add 0, delete 0, find 0/0
[14074.880000] Free swap = 0kB
[14074.880000] Total swap = 0kB
[14074.880000] 8192 pages RAM
[14074.880000] 820 pages reserved
[14074.880000] 2465 pages shared
[14074.880000] 6165 pages non-shared
[14074.880000] SLUB: Unable to allocate memory on node -1 (gfp=0x20)
[14074.880000] cache: kmalloc-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
[14074.880000] node 0: slabs: 0, objs: 0, free: 0
[14075.120000] ath: skbuff alloc of size 1926 failed
[14075.120000] dnscrypt-proxy: page allocation failure: order:0, mode:0x4020
[14075.120000] Call Trace:[<802663e8>] 0x802663e8
[14075.120000] [<802663e8>] 0x802663e8
[14075.120000] [<800ad368>] 0x800ad368
[14075.120000] [<800af668>] 0x800af668
[14075.120000] [<802d0000>] 0x802d0000
[14075.120000] [<800d2e60>] 0x800d2e60
[14075.120000] [<80071ca4>] 0x80071ca4
[14075.120000] [<80267834>] 0x80267834
[14075.120000] [<800721e0>] 0x800721e0
[14075.120000] [<800d4838>] 0x800d4838
[14075.120000] [<801d6c44>] 0x801d6c44
[14075.120000] [<814bc0c0>] 0x814bc0c0
[14075.120000] [<801d6be8>] 0x801d6be8
[14075.120000] [<814bc0c0>] 0x814bc0c0
[14075.120000] [<81fa6d4c>] 0x81fa6d4c
[14075.120000] [<8008e064>] 0x8008e064
[14075.120000] [<8009659c>] 0x8009659c
[14075.120000] [<8006da01>] 0x8006da01
[14075.120000] [<81fa4318>] 0x81fa4318
[14075.120000] [<80076300>] 0x80076300
[14075.120000] [<80076824>] 0x80076824
[14075.120000] [<80076a30>] 0x80076a30
[14075.120000] [<80089360>] 0x80089360
[14075.120000] [<80076c64>] 0x80076c64
[14075.120000] [<80062d2c>] 0x80062d2c
[14075.120000]
[14075.120000] Mem-Info:
[14075.120000] Normal per-cpu:
[14075.120000] CPU 0: hi: 0, btch: 1 usd: 0
[14075.120000] active_anon:614 inactive_anon:18 isolated_anon:0
[14075.120000] active_file:1164 inactive_file:1399 isolated_file:0
[14075.120000] unevictable:0 dirty:0 writeback:0 unstable:0
[14075.120000] free:68 slab_reclaimable:371 slab_unreclaimable:2725
[14075.120000] mapped:473 shmem:56 pagetables:85 bounce:0
[14075.120000] Normal free:272kB min:720kB low:900kB high:1080kB active_anon:2456kB inactive_anon:72kB active_file:4656kB inactive_file:5596kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:32512kB mlocked:0kB dirty:0kB writeback:0kB mapped:1892kB shmem:224kB slab_reclaimable:1484kB slab_unreclaimable:10900kB kernel_stack:368kB pagetables:340kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
[14075.120000] lowmem_reserve[]: 0 0
[14075.120000] Normal: 54*4kB 1*8kB 1*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 272kB
[14075.120000] 2619 total pagecache pages
[14075.120000] 0 pages in swap cache
[14075.120000] Swap cache stats: add 0, delete 0, find 0/0
[14075.120000] Free swap = 0kB
[14075.120000] Total swap = 0kB
[14075.120000] 8192 pages RAM
[14075.120000] 820 pages reserved
[14075.120000] 2465 pages shared
[14075.120000] 6165 pages non-shared
[14075.120000] SLUB: Unable to allocate memory on node -1 (gfp=0x20)
[14075.120000] cache: kmalloc-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
[14075.120000] node 0: slabs: 0, objs: 0, free: 0
[14075.360000] ath: skbuff alloc of size 1926 failed
[14075.360000] ath: skbuff alloc of size 1926 failed
[14075.370000] ath: skbuff alloc of size 1926 failed
[14075.370000] ath: skbuff alloc of size 1926 failed
[14075.380000] ath: skbuff alloc of size 1926 failed
[14075.380000] ath: skbuff alloc of size 1926 failed
[14075.390000] ath: skbuff alloc of size 1926 failed
[14075.390000] ath: skbuff alloc of size 1926 failed
[14075.400000] ath: skbuff alloc of size 1926 failed
[14075.400000] ath: skbuff alloc of size 1926 failed
[14075.410000] ath: skbuff alloc of size 1926 failed
[14075.410000] ath: skbuff alloc of size 1926 failed
[14075.420000] ath: skbuff alloc of size 1926 failed
[14075.420000] ath: skbuff alloc of size 1926 failed
[14075.420000] ath: skbuff alloc of size 1926 failed
[14075.430000] ath: skbuff alloc of size 1926 failed
[14075.430000] ath: skbuff alloc of size 1926 failed
[14075.440000] ath: skbuff alloc of size 1926 failed
[14075.440000] ath: skbuff alloc of size 1926 failed
[14075.450000] ath: skbuff alloc of size 1926 failed
[14075.450000] ath: skbuff alloc of size 1926 failed
[14075.460000] ath: skbuff alloc of size 1926 failed
[14075.460000] ath: skbuff alloc of size 1926 failed
[14075.470000] ath: skbuff alloc of size 1926 failed
[14075.470000] ath: skbuff alloc of size 1926 failed
[14075.480000] ath: skbuff alloc of size 1926 failed
[14075.480000] ath: skbuff alloc of size 1926 failed
[14075.490000] ath: skbuff alloc of size 1926 failed
[14075.490000] ath: skbuff alloc of size 1926 failed
[14075.500000] ath: skbuff alloc of size 1926 failed
[14075.500000] ath: skbuff alloc of size 1926 failed
[14075.500000] ath: skbuff alloc of size 1926 failed
[14075.510000] ath: skbuff alloc of size 1926 failed
[14075.510000] ath: skbuff alloc of size 1926 failed
[14075.520000] eth1: out of memory
System log:
May 19 22:50:09 OpenWrt kern.info kernel: emory on node -1 (gfp=0x20)
May 19 22:50:09 OpenWrt kern.warn kernel: [14073.920000] cache: kmalloc-4096, object size: 4096, buffer size: 4096, default order: 3, min order: 0
May 19 22:50:09 OpenWrt kern.warn kernel: [14073.920000] node 0: slabs: 0, objs: 0, free: 0
May 19 22:50:09 OpenWrt kern.err kernel: [14074.160000] ath: skbuff alloc of size 1926 failed
May 19 22:50:09 OpenWrt kern.warn kernel: [14074.160000] dnscrypt-proxy: page allocation failure: order:0, mode:0x4020
May 19 22:50:09 OpenWrt kern.warn kernel: [14074.160000] Call Trace:[<802663e8>] 0x802663e8
May 19 22:50:09 OpenWrt kern.warn kernel: [14074.160000] [<802663e8>] 0x802663e8
May 19 22:50:09 OpenWrt kern.warn kernel: [14074.160000] [<800ad368>] 0x800ad368
May 19 22:50:09 OpenWrt kern.warn kernel: [14074.160000] [<800af668>] 0x800af668
May 19 22:50:09 OpenWrt kern.warn kernel: [14074.160000] [<802d0000>] 0x802d0000
May 19 22:50:09 OpenWrt kern.warn kernel: [14074.160000] [<800d2e60>] 0x800d2e60
May 19 22:50:09 OpenWrt kern.warn kernel: [14074.160000] [<80071ca4>] 0x80071ca4