{
  "slug": "page-cache",
  "term": "Page cache",
  "aliases": [
    "Linux page cache"
  ],
  "definition": "The page cache is the kernel-managed memory that holds cached file contents for access and writeback.",
  "note": "Linux iomap manages cached folios and their up-to-date and dirty state. Its direct-I/O path still flushes dirty cached data and invalidates cached ranges where required, so bypassing cached transfers does not eliminate coherence work. [iomap]",
  "advantages": [
    "Can serve reusable file contents from memory."
  ],
  "limitations": [
    "A cached copy is not an independent backup or proof of durable storage."
  ],
  "related": [
    "buffered-io",
    "direct-io",
    "write-back-cache",
    "writeback-error"
  ],
  "citations": [
    {
      "id": "iomap",
      "label": "Linux v6.17 iomap",
      "title": "Linux v6.17: iomap supported file operations, sections 2.2.1-2.2.3.",
      "url": "https://www.kernel.org/doc/html/v6.17/filesystems/iomap/operations.html",
      "accessed": "2026-10-14"
    }
  ],
  "status": "shipping",
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-14"
}