--- title: vLLM Teardown Part 2: The Virtual Memory for LLMs description: A deep dive into how vLLM manages GPU memory for serving large language models at scale. Covers PagedAttention (borrowing OS paging to eliminate 60-80% memory... canonical: https://daily.dev/posts/vllm-teardown-part-2-the-virtual-memory-for-llms-uzjhgrxwa twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: vLLM Teardown Part 2: The Virtual Memory for LLMs | daily.dev og:description: A deep dive into how vLLM manages GPU memory for serving large language models at scale. Covers PagedAttention (borrowing OS paging to eliminate 60-80% memory... og:url: https://daily.dev/posts/vllm-teardown-part-2-the-virtual-memory-for-llms-uzjhgrxwa og:image: https://api.daily.dev/og/posts/UzJHGRxWA.png og:image:alt: vLLM Teardown Part 2: The Virtual Memory for LLMs og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # vLLM Teardown Part 2: The Virtual Memory for LLMs **[Medium](https://daily.dev/sources/medium_js)** · 6 min read · 0 upvotes · 0 comments ## Summary A deep dive into how vLLM manages GPU memory for serving large language models at scale. Covers PagedAttention (borrowing OS paging to eliminate 60-80% memory waste), the Scheduler's optimistic admission control with preemption via recompute or swap, Automatic Prefix Caching using hash-based copy-on-write to avoid redundant computation for shared system prompts, and Chunked Prefill to prevent head-of-line blocking from large prompts. Includes practical troubleshooting tips for common production issues like high memory usage, frequent preemptions, and stream freezes. Briefly compares vLLM to SGLang and previews upcoming topics like speculative decoding and multi-engine routing. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Inside vLLM: Anatomy of a High-Throughput LLM Inference System \(2025\)](https://daily.dev/posts/inside-vllm-anatomy-of-a-high-throughput-llm-inference-system-2025--5fkcjpua7) · Hacker News · 2 upvotes · 0 comments - [Attention Mechanisms in LLMs, clearly explained](https://daily.dev/posts/attention-mechanisms-in-llms-clearly-explained-srfzv2qkd) · Daily Dose of Data Science \| Avi Chawla \| Substack · 0 upvotes · 0 comments - [Continuous Batching Mechanics: The Scheduler Behind vLLM, TGI, and SGLang](https://daily.dev/posts/continuous-batching-mechanics-the-scheduler-behind-vllm-tgi-and-sglang-9x0j2tj3u) · DigitalOcean Community · 0 upvotes · 0 comments - [Why vLLM is the best choice for AI inference today](https://daily.dev/posts/why-vllm-is-the-best-choice-for-ai-inference-today-7zxdzzpx7) · Red Hat Developer · 0 upvotes · 0 comments --- Tags: [#ai-inference](https://daily.dev/tags/ai-inference), [#vllm](https://daily.dev/tags/vllm) [View this post on daily.dev](https://daily.dev/posts/vllm-teardown-part-2-the-virtual-memory-for-llms-uzjhgrxwa) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"vLLM Teardown Part 2: The Virtual Memory for LLMs","url":"https://daily.dev/posts/vllm-teardown-part-2-the-virtual-memory-for-llms-uzjhgrxwa","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/vllm-teardown-part-2-the-virtual-memory-for-llms-uzjhgrxwa"},"datePublished":"2026-07-21T19:30:49.826Z","dateModified":"2026-07-21T19:31:13.058Z","description":"A deep dive into how vLLM manages GPU memory for serving large language models at scale. 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