{"id":79051,"date":"2020-04-23T19:43:32","date_gmt":"2020-04-23T17:43:32","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/novyj-metod-upravleniya-pamyatyu-ot-facebook"},"modified":"2020-04-23T19:43:32","modified_gmt":"2020-04-23T17:43:32","slug":"novyj-metod-upravleniya-pamyatyu-ot-facebook","status":"publish","type":"post","link":"https:\/\/prohoster.info\/en\/blog\/news\/novyj-metod-upravleniya-pamyatyu-ot-facebook","title":{"rendered":"New memory management method from Facebook","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

One of the members of the social network development team Facebook<\/strong>, Roman Gushchin<\/strong>, proposed in the developers' mailing list a set of patches for the Linux kernel<\/strong>, aimed at improving memory handling through the implementation of a new memory management controller \u2014 slab (slab memory controller)<\/strong>.<\/p>\n

Slab allocation<\/strong> is a memory management mechanism designed for more efficient memory allocation and significant fragmentation reduction. The basis of this algorithm is to retain allocated memory containing an object of a specific type and to reuse that memory during the next allocation for an object of the same type. This method was first introduced in SunOS by Jeff Bonwick and is now widely used in the kernels of many Unix operating systems, including FreeBSD and Linux.<\/p>\n

The new controller is based on transferring slab accounting from the memory page level to the kernel object level, which allows the sharing of a single slab page across different cgroups instead of allocating a separate cache for each cgroup.<\/p>\n

Test results indicate that the proposed memory management method increases the efficiency<\/strong> of slab usage by up to 45%<\/strong>, as well as reduces the overall memory consumption by the OS kernel. Additionally, by reducing the number of slab pages allocated, the overall memory fragmentation decreases, which positively affects system performance.<\/p>\n

The new controller has been tested on Facebook's production servers for several months now, and this testing can be considered successful: with no loss in performance and an increase in error rates, there has been a clear reduction in memory usage \u2014 on some servers by up to 1GB. This figure is somewhat subjective; for example, previously conducted tests showed slightly lower results:<\/p>\n