Hacker News with Generative AI: Memory Management

Java 24 to Reduce Object Header Size and Save Memory (infoq.com)
JEP 450 (Compact Object Headers) has been targeted for delivery in JDK 24, and has already been merged to main.

Java, Programming Languages, Memory Management, Performance Optimization

10 points by 0x54MUR41 2 days ago | 4 comments

Speculations on arenas and custom strings in C++ (nullprogram.com)
My techniques with arena allocation and strings are oriented around C. I’m always looking for a better way, and lately I’ve been experimenting with building them using C++ features. What are the trade-offs? Are the benefits worth the costs? In this article I lay out my goals, review implementation possibilities, and discuss my findings. Following along will require familiarity with those previous two articles.

C++, Programming, Memory Management, Optimization, Strings

46 points by KeyurRamoliya 11 days ago | 6 comments

Memory64 (github.com/WebAssembly)
This page describes a proposal to support linear memory of sizes larger than 232 bits. It provides no new instructions, but instead extends the currently existing instructions to allow 64-bit indexes.

WebAssembly, Memory Management, Programming Languages

83 points by tosh 14 days ago | 50 comments

Bounded Flexible Arrays in C (kernel.org)
Large projects written in C, especially those written close to the hardware layer like Linux, have long treated the language as a high-level assembler.

C, Programming Languages, Operating Systems, Kernel Development, Memory Management

12 points by fanf2 21 days ago | 0 comments

Tip of the day #2: A safer arena allocator (gaultier.github.io)
The most transformative action you can do to dramatically improve your code in a programming language where you are in control of the memory is: to use arenas.

Programming, Memory Management, Software Development, Optimization

23 points by broken_broken_ 22 days ago | 2 comments

Unleashing Power: Enabling Super Pages on the RPi (mairacanal.github.io)
Unleashing the power of 3D graphics in the Raspberry Pi is a key commitment for Igalia through its collaboration with Raspberry Pi. The introduction of Super Pages for the Raspberry Pi 4 and 5 marks another step in this journey, offering some performance enhancements and more efficient memory usage. In this post, we’ll dive deep into the technical details of Super Pages, discuss the challenges we faced during implementation, and illustrate the benefits this feature brings to the Raspberry Pi ecosystem.

Raspberry Pi, Software, Operating Systems, Performance, Memory Management

24 points by JNRowe 23 days ago | 0 comments

Using less memory to look up IP addresses in Mess With DNS (jvns.ca)
I’ve been having problems for the last 3 years or so where Mess With DNS periodically runs out of memory and gets OOM killed.

DNS, Memory Management, Optimization

137 points by todsacerdoti 25 days ago | 41 comments

Are you sure you want to use MMAP in your database management system? (2022) (cs.cmu.edu)
Memory-mapped (MMAP) file I/O is an OS-provided feature that maps the contents of a file on secondary storage into a program’s address space.

Operating Systems, Memory Management, Performance Optimization, File Systems

15 points by tosh 26 days ago | 2 comments

A deep dive into Linux's new mseal syscall (trailofbits.com)
If you love exploit mitigations, you may have heard of a new system call named mseal landing into the Linux kernel’s 6.10 release, providing a protection called “memory sealing.” Beyond notes from the authors, very little information about this mitigation exists. In this blog post, we’ll explain what this syscall is, including how it’s different from prior memory protection schemes and how it works in the kernel to protect virtual memory.

Linux, Security, Kernel, Operating Systems, Memory Management

252 points by todsacerdoti 27 days ago | 54 comments

Smart pointers for the kernel (lwn.net)
Rust has a plethora of smart-pointer types, including reference-counted pointers, which have special support in the compiler to make them easier to use. The Rust-for-Linux project would like to reap those same benefits for its smart pointers, which need to be written by hand to conform to the Linux kernel memory model. Xiangfei Ding presented at Kangrejos about the work to enable custom smart pointers to function the same as built-in smart pointers.

Rust, Linux Kernel, Programming Languages, Memory Management

169 points by signa11 34 days ago | 114 comments

How Ruby Uses Memory (2015) (sitepoint.com)
I’ve never met a developer who complained about code getting faster or taking up less RAM. In Ruby, memory is especially important, yet few developers know the ins-and-outs of why their memory use goes up or down as their code executes. This article will start you off with a basic understanding of how Ruby objects relate to memory use, and we’ll cover a few common tricks to speed up your code while using less memory.

Programming, Ruby, Performance Optimization, Memory Management

16 points by thunderbong 38 days ago | 0 comments

Working Set Size Estimation (2018) (brendangregg.com)
The Working Set Size (WSS) is how much memory an application needs to keep working.

Performance Optimization, Memory Management, System Monitoring, Operating Systems

30 points by pncnmnp 48 days ago | 2 comments

Tracking (C++) Shared Pointer Leaks (ibob.bg)
Let’s talk about shared pointer leaks. In a piece of software which makes heavy use of shared pointers such leaks are possible. They are very hard and annoying to deal with. They are also very hard to identify in the first place.

C++, Memory Management, Debugging, Software Development

28 points by signa11 50 days ago | 9 comments

Revisiting the DOS Memory Models (blogsystem5.substack.com)
At the beginning of the year, I wrote a bunch of articles on the various tricks DOS played to overcome the tight memory limits of x86’s real mode. There was one question that came up and remained unanswered: what were the various “models” that the compilers of the day offered?

Operating Systems, Programming, History, DOS, Memory Management

8 points by thunderbong 50 days ago | 2 comments

The Case of the Missing Increment (computerenhance.com)
Computer Enhance was never meant to be a place for publishing novel investigations into software performance, but sometimes it happens by accident. We already saw this once when bonus materials for the Performance-Aware Programming course lead us to discover a previously undocumented 16-ahead mapping pattern in the Windows memory manager.

Software Performance, Windows, Programming, Memory Management

15 points by eapriv 55 days ago | 1 comments

Interning in Go (medium.com)
Go 1.23 comes with a new package unique implementing interning, and a blog post about it. Interning is re-using objects of equal value instead of keeping duplicate equal objects in memory. It is intended to reduce memory usage.

Go, Programming Languages, Memory Management, Optimization

140 points by todsacerdoti 66 days ago | 46 comments

Generic Freelist Allocator for Go (pkg.go.dev)
This package is not in the latest version of its module.

Go, Programming, Memory Management, Data Structures

10 points by Snawoot 68 days ago | 3 comments

Nesting Allocators (2023) (yoshuawuyts.com)
I regularly point people to Tmandry's 2021 post "Contexts and Capabilities in Rust". While nobody is actively working on the design at the moment, it's more because of prioritization than anything else. It seems like it could make certain usage patterns a lot nicer in Rust, and one of those is probably working with custom allocators. I've been working a lot with slab allocators recently, and I'd love it if they were easier to work with in Rust.

Rust, Memory Management, Programming Languages

99 points by todsacerdoti 68 days ago | 11 comments

What is the best pointer tagging method? (coredumped.dev)
In this post, we are going to take a deep dive into pointer tagging, where metadata is encoded into a word-sized pointer. Doing so allows us to keep a compact representation that can be passed around in machine registers. This is very common in implementing dynamic programming languages, but can really be used anywhere that additional runtime information is needed about a pointer.

Programming, Memory Management, Performance Optimization

4 points by rrampage 72 days ago | 0 comments

What is the best pointer tagging method? (coredumped.dev)
In this post, we are going to take a deep dive into pointer tagging, where metadata is encoded into a word-sized pointer. Doing so allows us to keep a compact representation that can be passed around in machine registers. This is very common in implementing dynamic programming languages, but can really be used anywhere that additional runtime information is needed about a pointer.

Programming, Optimization, Memory Management, Runtime Efficiency

115 points by celeritascelery 73 days ago | 31 comments

Zig's Memcpy, CopyForwards and CopyBackwards (openmymind.net)

Zig, Programming Languages, Memory Management

34 points by todsacerdoti 79 days ago | 8 comments

Crash the GC with Random Values in Unsafe.Pointers (philpearl.github.io)

Programming, C#, Garbage Collection, Memory Management

27 points by todsacerdoti 82 days ago | 7 comments

Twenty Years of Valgrind (2022) (nnethercote.github.io)

Software, Tools, Security, Memory Management, Programming

223 points by fanf2 85 days ago | 60 comments

Adding 16 kb page size to Android (googleblog.com)