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,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8E296C00A89 for ; Mon, 2 Nov 2020 19:29:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9E5820731 for ; Mon, 2 Nov 2020 19:29:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=waffle.tech header.i=@waffle.tech header.b="tOhASUv7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726369AbgKBT3H (ORCPT ); Mon, 2 Nov 2020 14:29:07 -0500 Received: from waffle.tech ([104.225.250.114]:47534 "EHLO mx.waffle.tech" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725806AbgKBT3H (ORCPT ); Mon, 2 Nov 2020 14:29:07 -0500 Received: from mx.waffle.tech (unknown [10.50.1.6]) by mx.waffle.tech (Postfix) with ESMTP id 345D694410; Mon, 2 Nov 2020 12:29:05 -0700 (MST) DKIM-Filter: OpenDKIM Filter v2.11.0 mx.waffle.tech 345D694410 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=waffle.tech; s=mx; t=1604345345; bh=XFBjJtnukioeL5UJtcUFhV2fW6hRqwuFlMVY3U1xeOY=; h=Date:From:Subject:To:Cc:In-Reply-To:References:From; b=tOhASUv7r6qHc2ILE11sJxyiSmXspmPEi2c89n8AfbA/215WmfShF1ZXwYmdKDiom LU101kBRDrXuE1Jz2TI0k4+VQCXz455LIBkvULm6qafw/6hb64qmI7+emHnuEDmJFd HP4mJ2BKAurv6P9PAzdYj7E+Q83nfFP6ZbgDz95w= Received: from waffle.tech ([10.50.1.3]) by mx.waffle.tech with ESMTPSA id X0mECwFeoF+RDgkAQqPLoA (envelope-from ); Mon, 02 Nov 2020 12:29:05 -0700 MIME-Version: 1.0 Date: Mon, 02 Nov 2020 19:29:04 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Mailer: RainLoop/1.14.0 From: louis@waffle.tech Message-ID: <041d24ef26dc5c763c5af6d6de7434ef@waffle.tech> Subject: Re: [PATCH] btrfs: balance RAID1/RAID10 mirror selection To: "Nikolay Borisov" , "Wang Yugui" Cc: linux-btrfs@vger.kernel.org In-Reply-To: References: <8541d6d7a63e470b9f4c22ba95cd64fc@waffle.tech> <20201023153814.643F.409509F4@e16-tech.com> Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Good points. I'll move it into 'struct btrfs_fs_info', look at making it = a per-cpu variable, and do some testing with perf (later this week hopefu= lly).=0A=0ALouis=0A=0AOctober 23, 2020 1:42 AM, "Nikolay Borisov" wrote:=0A=0A> On 23.10.20 =D0=B3. 10:38 =D1=87., Wang Yugui = wrote:=0A> =0A>> Hi, Louis Jencka=0A>> =0A>> Can we move 'atomic_t rr_cou= nter' into 'struct btrfs_fs_info' to=0A>> support multiple mounted btrfs = filesystem?=0A> =0A> And introduce constant cache line pings for every re= ad. This thing needs=0A> to be tested under load with perf to see what ki= nd of overhead the=0A> shared atomic_t counter adds. My hunch is this sho= uld really be a=0A> per-cpu variable.=0A> =0A>