From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31FA2C433DB for ; Fri, 12 Mar 2021 15:42:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3622164F53 for ; Fri, 12 Mar 2021 15:41:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3622164F53 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=flapflap.eu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9830B6B0074; Fri, 12 Mar 2021 10:41:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 9329F6B0075; Fri, 12 Mar 2021 10:41:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 820DD6B0078; Fri, 12 Mar 2021 10:41:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0201.hostedemail.com [216.40.44.201]) by kanga.kvack.org (Postfix) with ESMTP id 68D806B0074 for ; Fri, 12 Mar 2021 10:41:58 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 28D5481C5 for ; Fri, 12 Mar 2021 15:41:58 +0000 (UTC) X-FDA: 77911637916.03.4998577 Received: from server02.webapps.manitu.net (server02.webapps.manitu.net [217.11.48.34]) by imf02.hostedemail.com (Postfix) with ESMTP id 21C984080F52 for ; Fri, 12 Mar 2021 15:41:46 +0000 (UTC) Received: from webmail.manitu.de (localhost [127.0.0.1]) by server02.webapps.manitu.net (Postfix) with ESMTP id 12AEB660217; Fri, 12 Mar 2021 16:41:55 +0100 (CET) MIME-Version: 1.0 Date: Fri, 12 Mar 2021 16:41:55 +0100 From: Peter Weber To: Matthew Wilcox Cc: linux-mm@kvack.org Subject: Re: Is anonymous memory part of the page cache on Linux? In-Reply-To: <20210312151540.GC2577561@casper.infradead.org> References: <20210312151540.GC2577561@casper.infradead.org> User-Agent: Roundcube Webmail/1.4.11 Message-ID: X-Sender: peter.weber@flapflap.eu Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-manitu-Webmail-Sender: cHdlYmVyQGZsYXBmbGFwLmV1 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 21C984080F52 X-Stat-Signature: f9reph6werjhh5cnpdntqofiuhpa1jw9 Received-SPF: none (flapflap.eu>: No applicable sender policy available) receiver=imf02; identity=mailfrom; envelope-from=""; helo=server02.webapps.manitu.net; client-ip=217.11.48.34 X-HE-DKIM-Result: none/none X-HE-Tag: 1615563706-694600 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Thank you Matthew! Am 2021-03-12 16:15, schrieb Matthew Wilcox: > The wikipedia diagram is wrong. Anonymous memory is not handled by the > page cache. Is it roughly right to say, that the virtual memory uses page tables to handle anonymous memory? > Anonymous pages enter the storage stack via swap; they are > found in the page tables, sent to the swap cache and then written to > swap devices or swap files. Filesystems may get involved at that > point, > but not always. And the page cache doesn't handle anonymous memory - even when it is swapped? > There are other weird things in the wikipedia diagram, like Direct I/O > being seemingly detached from applications, and not appearing to pass > through the VFS. I'm not an expert. Maybe I should add at least note about that on Wikipedia?