https://nalar.dev/tags/page-cache/ Recent content in Page Cache on Nalar Hugo en-us Wed, 16 Sep 2026 00:00:00 +0700 https://nalar.dev/linux-readahead-expands-sequential-page-cache-reads/ Wed, 16 Sep 2026 00:00:00 +0700 https://nalar.dev/linux-readahead-expands-sequential-page-cache-reads/ <p>A buffered file read can cause Linux to fetch more data than the application explicitly requested. The extra I/O is readahead: the kernel populates nearby page-cache folios in anticipation of continued access.</p> <p>This behavior sits between application read size and storage request size. A process may issue modest <code>read()</code> calls while the kernel submits larger reads to keep later accesses from waiting on storage.</p> <h2 id="readahead-is-page-cache-speculation">Readahead is page-cache speculation</h2> <p>Buffered file I/O normally passes through the page cache. When requested file data is absent, the kernel must arrange I/O for that miss. The readahead path can extend that operation across additional folios that are not yet present in the cache.</p>