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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2A22BFF885D for ; Sun, 26 Apr 2026 20:44:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7703B6B0005; Sun, 26 Apr 2026 16:44:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 721086B008A; Sun, 26 Apr 2026 16:44:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 636AF6B008C; Sun, 26 Apr 2026 16:44:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 4DC6D6B0005 for ; Sun, 26 Apr 2026 16:44:57 -0400 (EDT) Received: from smtpin15.hostedemail.com (lb01b-stub [10.200.18.250]) by unirelay03.hostedemail.com (Postfix) with ESMTP id DC50AA0601 for ; Sun, 26 Apr 2026 20:44:56 +0000 (UTC) X-FDA: 84701886192.15.7EF27EC Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf24.hostedemail.com (Postfix) with ESMTP id A7C33180002 for ; Sun, 26 Apr 2026 20:44:53 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=S4pLnzvZ; spf=none (imf24.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=pass (policy=none) header.from=infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1777236295; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=I/fTyPP7bqTqt5fNYUoxgKpJh1vpEuR3aFaCVhySFZA=; b=uSdfvf8LY0CVhZOG1nf19UkhPjx5MwU9uP3TNU5usA7NHu8Qg3lhEqyA67M+WXxzEDSkD3 HXWOfJ701kY5jaRtetn67zNaqkqvQI8LdFFh/UNPdC4GST3KPCCm/JQity1x6gPcb1G4Fg THNYuZ/QnNMZ6rc7B19lwEcn1MfYgI4= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=S4pLnzvZ; spf=none (imf24.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=pass (policy=none) header.from=infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777236295; a=rsa-sha256; cv=none; b=NzpOGpQ2JBlhZfNMjUYSs6SwqfUDwop6dImYiIZZWifVGU84uHXiGByOT2WeQicnli7KSa y9nIzS6m2ORMQvZVHiw6A/LqpiPl2R1QvGn3QFocF/LvqqI599b9tLUc5pda/o/j91JFV6 pEPCAX8iW0XzAchM++3hzHGxs/qnKS0= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=I/fTyPP7bqTqt5fNYUoxgKpJh1vpEuR3aFaCVhySFZA=; b=S4pLnzvZn8wrgvL75yH/njOHFS qi3So9o5mDIDheJ6DeCD+gLAKuPaApFP2a8iw+bbRYYCoD/CnPn4F/8/qF9X0VR82yMqoVLxjrGXD TJeQqJOfcmOUSNfU3NU4CENu6sp4ZXRaXpZAhne0g/1iAKHtEthPIWv7t8ZaiUYqynOAJAElxhNWZ xEfa8BbC6KdRILxUzJq1iyPFoHLd/DVKd4aDMy+TQq7ZRG161vtP/TDWWUAV4n7Q/AaBcDJxsR6C8 LjDHkjlkKkPE5BdVjJlG2EGpbcUcbDhERYKOxZ5FbtGCS/ZPdO1ogRAMxRRB8lLq9Vn0ntAHBRU81 GOxj8lHw==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1wH6LD-00000000zSI-3g9m; Sun, 26 Apr 2026 20:44:35 +0000 Date: Sun, 26 Apr 2026 21:44:35 +0100 From: Matthew Wilcox To: Jeff Layton Cc: Alexander Viro , Christian Brauner , Jan Kara , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Mike Snitzer , Jens Axboe , Ritesh Harjani , Christoph Hellwig , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Chuck Lever , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/4] mm: kick writeback flusher for IOCB_DONTCACHE with targeted dirty tracking Message-ID: References: <20260426-dontcache-v3-0-79eb37da9547@kernel.org> <20260426-dontcache-v3-2-79eb37da9547@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260426-dontcache-v3-2-79eb37da9547@kernel.org> X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: A7C33180002 X-Stat-Signature: k5x1u197e6nem6entmcipx3673a4kjsi X-HE-Tag: 1777236293-130805 X-HE-Meta: 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 17rrGbg5 V85eVYXSI3fgH46mTg653BtyOX5QYHC8bHU1QgmhCkiR6hWR6NAvwF6lLVixRwWP0H84CdCmZ4CWZquvlCfy+mo4Dwpc94JsGFObn1FY3a9DgNUyPW32rg9PLimSXbSdmJNJPdJ2cm7JDhyMckMRD4lywTCTwiaDhAGfmgOzDqTLPdAy7OHn4pyZburdgI5flwLKyfNh5sL4c0PaDgCyulnSAf8J02nFbjGNmdz2QZxmrbEm1TuXD1uAzc7zDZShAzXKnCfwNfb7duFZf9+tZ4teMfimfT3/TeJIjPZZ5nYKEsLcQHFxozHQ9nIhWD23/YJql0kWzI7wx/Z5AQrNuWyZP2xoS+yfLrJzw+oqvFN33GJVXNoK28btWTA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, Apr 26, 2026 at 07:56:08AM -0400, Jeff Layton wrote: > Mixed-mode noisy neighbor (dontcache writer + buffered readers): > baseline patched change > writer (MB/s) 1297.6 1471.1 +13.4% > readers avg (MB/s) 855.0 462.4 -45.9% hm. This wasn't what I thought of when I thought of "noisy neighbour". I'd have process A doing DONTCACHE writes to file A and process B doing normal buffered writes to file B.