An investigation reveals that Java 8 processes can report virtual memory usage exceeding 50 GB due to extensive address space allocation by glibc’s arena mechanism, not actual physical memory, and explains how environment variables like MALLOC_ARENA_MAX can limit this VIRT growth.
This article explains how memory serves as the main storage for processes, introduces the concepts of virtual memory and paging, and describes how page tables and multi‑level paging enable efficient address translation, isolation, and sharing in modern operating systems.
This article explains the fundamentals of computer memory, covering linear addresses, virtual memory translation, paging mechanisms, page size queries, and the structure of multi‑level page tables used by Linux to efficiently map virtual to physical memory.
This article explains how computer memory works, covering physical memory characteristics, address spaces, RAM's random access nature, virtual memory translation, paging mechanisms, page size queries, and multi‑level page tables that enable efficient and secure memory management in Linux.
This article explains the need for virtual memory in Linux, describes its implementation mechanisms such as swap space and lazy allocation, and details the typical layout of the kernel and user address spaces, including high‑memory handling and zone mapping.
This article explains Linux kernel memory management by describing how user‑level malloc allocates virtual memory, how page tables map virtual to physical addresses, and how the hardware‑triggered page‑fault mechanism ultimately provides the needed physical pages.
This article explains Linux’s hardware‑independent three‑tier physical memory model (node, zone, page) and the three‑level virtual memory page‑table hierarchy (PGD, PMD, PTE), including key macros, structure definitions, and the macros used to walk the tables from a virtual address to a physical page.
This article explains Linux's memory architecture, covering physical and virtual memory differences between 32‑bit and 64‑bit systems, memory zones, the buddy allocator, page reclamation, and swap handling, providing essential knowledge for performance tuning and system optimization.
While in‑memory databases promise blazing speed, developers often overlook critical issues such as memory capacity limits, the complexities of moving from 32‑bit to 64‑bit architectures, and the constraints imposed by virtual memory and swap space, all of which can dramatically affect performance and scalability.
