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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AA1B0C32771 for ; Sun, 18 Sep 2022 11:03:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229614AbiIRLDL (ORCPT ); Sun, 18 Sep 2022 07:03:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39820 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbiIRLDK (ORCPT ); Sun, 18 Sep 2022 07:03:10 -0400 Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05CE925E9F for ; Sun, 18 Sep 2022 04:03:09 -0700 (PDT) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id DD7DA5C02CC; Sun, 18 Sep 2022 07:03:06 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute5.internal (MEProxy); Sun, 18 Sep 2022 07:03:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rath.org; h=cc :content-transfer-encoding:content-type:date:date:from:from :in-reply-to:message-id:mime-version:reply-to:sender:subject :subject:to:to; s=fm3; t=1663498986; x=1663585386; bh=V3kEsfeDBJ N4CdGXOE4NkgGPA+jJODsqE1SbYEllR3I=; b=oNXvtddFP6PtVB1pKkkYgg4te/ sIOO5eNwPbMq/loNy6INkpm9sqW/kcHI95/1mUh8A6aoiqxPa9Lkq2ERYfBIt6qn XXM4riEx2DLvAPA5mQyfMlkYtfbOucp8RSwY0JHaX89d3rnJXgXI2ThlOPYxE0OO RNb54w9Db6bDGbwIDGkwWkZE9L7isTbk3pC5sDl9eZJwXZMxf/49yCIWx/eKcSdN OANpAdyWlNHmXx9PE3sWa3MQnWb3lzdX6c0oLIFNFYRnam+RxS4LsCf9qBWW1+1a CDjQVTHgV6FjcQv2qj162q5uVwxAp8fB2jOrAAD0SJKEk14aKHX2HUZDREbA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:date:feedback-id:feedback-id:from:from:in-reply-to :message-id:mime-version:reply-to:sender:subject:subject:to:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; t=1663498986; x=1663585386; bh=V3kEsfeDBJN4CdGXOE4NkgGPA+jJ ODsqE1SbYEllR3I=; b=wwGAD7c7mptySBOhYxf1Ikl8uEvDcnewhg5tvNrSLU5J 7sO25KFSxCO0g/LaEC7DGjJnWxRmV/fWpaX9Ji5edet5zZD624SLc29aCnr6SnsF R2JzktmGT5W9PkS1Ro24nplYLx4DnsMHICJNooY9ILNmvqw7iQY48mdclX27gVNU xWmgw071yogzK6TaAzLbWgYZA3V8t2iAzbUp20DIReUo4B30ImzJNFI8I6mwmR1p w80hFCcF+XrT9dTuv4AqJY2Age5V2SA3LX0rfg4sFe0O25ze9WWDQjzVsCBYI/R1 ASfnY2zAcTmEdkeF77TJYxMoJzqS08rdQVNaKwk0Tw== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvfedrfedvhedgfeekucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvufffkfgfgggtgfesthhqtddttderjeenucfhrhhomheppfhikhholhgr uhhsucftrghthhcuoefpihhkohhlrghushesrhgrthhhrdhorhhgqeenucggtffrrghtth gvrhhnpeeftefhgfejhfelkeduieeludeuffduvedvveefkeevtdevgeevfeejgfdvuedt keenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpefpih hkohhlrghushesrhgrthhhrdhorhhg X-ME-Proxy: Feedback-ID: i53a843ae:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Sun, 18 Sep 2022 07:03:06 -0400 (EDT) Received: from vostro.rath.org (vostro [192.168.12.4]) by ebox.rath.org (Postfix) with ESMTPS id CAF10670; Sun, 18 Sep 2022 11:03:04 +0000 (UTC) Received: by vostro.rath.org (Postfix, from userid 1000) id 4985AD8013; Sun, 18 Sep 2022 12:03:04 +0100 (BST) From: Nikolaus Rath To: Linux FS Devel , miklos Subject: Should FUSE set IO_FLUSHER for the userspace process? Mail-Copies-To: never Mail-Followup-To: Linux FS Devel , miklos Date: Sun, 18 Sep 2022 12:03:04 +0100 Message-ID: <87mtaxt05z.fsf@vostro.rath.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Hi, Should the FUSE kernel driver perhaps set PR_SET_IO_FLUSHER for the FUSE userspace process daemon when a connection is opened? If I understand correctly, this is necessary to avoid a deadlocks if the kernel needs to reclaim memory that has to be written back through FUSE. I don't think it's possible to do this in userspace, since the process may lack the necessary capabilities. Best, -Nikolaus --=20 GPG Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F =C2=BBTime flies like an arrow, fruit flies like a Banana.=C2= =AB