Is memory usage on the server correct?

Question

CentOS

I have a parser on the server.
Initially the memory was 1GB
In the ISP control panel on the graph, the memory was consumed by less than half within 2 weeks.
Suddenly it rose sharply to 90-95%
I wrote to the hosting TP, asked why the load had grown so much, they answered me that everything was fine on the server, all scripts were working normally.
I increased the tariff to 2GB of memory and again grew to 90-95%,
I increased it to 4GB - the same thing.
Tell me is this normal or not?
The parser itself actually works for me no more than 10 minutes per hour (updated).
In php.ini, memeri_limit set -1, made 2048M (with 4GB server memory) result 0
99%

Thank you!