On 07.04.2021 14:47, Bharata B Rao wrote: > On Wed, Apr 07, 2021 at 01:07:27PM +0300, Kirill Tkhai wrote: >>> Here is how the calculation turns out to be in my setup: >>> >>> Number of possible NUMA nodes = 2 >>> Number of mounts per container = 7 (Check below to see which are these) >>> Number of list creation requests per mount = 2 >>> Number of containers = 10000 >>> memcg_nr_cache_ids for 10k containers = 12286 >> >> Luckily, we have "+1" in memcg_nr_cache_ids formula: size = 2 * (id + 1). >> In case of we only multiplied it, you would have to had memcg_nr_cache_ids=20000. > > Not really, it would grow like this for size = 2 * id > > id 0 size 4 > id 4 size 8 > id 8 size 16 > id 16 size 32 > id 32 size 64 > id 64 size 128 > id 128 size 256 > id 256 size 512 > id 512 size 1024 > id 1024 size 2048 > id 2048 size 4096 > id 4096 size 8192 > id 8192 size 16384 > > Currently (size = 2 * (id + 1)), it grows like this: > > id 0 size 4 > id 4 size 10 > id 10 size 22 > id 22 size 46 > id 46 size 94 > id 94 size 190 > id 190 size 382 > id 382 size 766 > id 766 size 1534 > id 1534 size 3070 > id 3070 size 6142 > id 6142 size 12286 Oh, thanks, I forgot what power of two is :) >> >> Maybe, we need change that formula to increase memcg_nr_cache_ids more accurate >> for further growths of containers number. Say, >> >> size = id < 2000 ? 2 * (id + 1) : id + 2000 > > For the above, it would only be marginally better like this: > > id 0 size 4 > id 4 size 10 > id 10 size 22 > id 22 size 46 > id 46 size 94 > id 94 size 190 > id 190 size 382 > id 382 size 766 > id 766 size 1534 > id 1534 size 3070 > id 3070 size 5070 > id 5070 size 7070 > id 7070 size 9070 > id 9070 size 11070 > > All the above numbers are for 10k memcgs. I mean the number of containers bigger then your 10000.
