July 2025
Intermediate to advanced
492 pages
8h 23m
Japanese
Content preview from Linuxカーネルプログラミング 第2版
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6章カーネルメモリ確保
この章ではカーネルメモリの確保と解放について説明します。モジュールを使った効率のよいメモリの扱い方についても解説します。
前半ではカーネルの2つの主要なメモリ確保について説明します。それぞれページアロケータとスラブアロケータです。前者はバディシステムアロケータとも呼ばれます。これらAPIについて、使い方だけではなくメモリ効率が悪くなる場合と、それを解決する方法を説明します。後半では、カスタムスラブキャッシュの作成と、vmalloc、そして状況に応じた適切なAPIの選択について説明します。またメモリの回収、OOM（Out of Memory）キラー、デマンドページングについても説明します。
6.1 カーネルメモリアロケータの概要
ページアロケータはページ単位でメモリを扱います。これは物理メモリの空き領域を効率的に管理するためのものです。
しかしページアロケータだけではページサイズ未満のメモリ領域をうまく扱えないため、他のアロケータもあります。その1つがスラブアロケータです。スラブアロケータの実装にはSLAB、SLUB、SLOBの3つがあり、デフォルトはSLUBです。詳細は後述します。
図6-1のようにスラブアロケータはページアロケータの上位に位置します。カーネルのサブシステムやモジュール、ドライバはページアロケータとスラブアロケータのどちらからもメモリを獲得、解放できます。物理メモリの割り当てはページアロケータだけが実施します。
図6-1 スラブアロケータとページアロケータの関係 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.