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[2620:137:e000::1:20]) by mx.google.com with ESMTP id h12-20020a63530c000000b00477dc113782si38553489pgb.600.2023.01.19.09.42.26; Thu, 19 Jan 2023 09:42:31 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=EdWgIYtu; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e header.b=lDnycYey; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230137AbjASQgb (ORCPT + 45 others); Thu, 19 Jan 2023 11:36:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230043AbjASQg1 (ORCPT ); Thu, 19 Jan 2023 11:36:27 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A2446EA2 for ; Thu, 19 Jan 2023 08:36:25 -0800 (PST) Date: Thu, 19 Jan 2023 17:36:22 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1674146183; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=AQh0swIanCssR3rlyr5cq60y9iMeZJZy8kioKjVR4fc=; b=EdWgIYtuPFXzFTmCN3Bfa+7uV+Bd5X3wJepa9+qR6M8gxf8KOJtOgAdL2ZrdOJBzj4RmV1 HKv++sFDw5ER2lFUB/wYyAQmSZTe3wdrSW9NAviueW+qBiIsMFe99mNqrMPkQ6vvoFP8Eh ECqBFAMquJhMTewq4sjaLwZ9/J875gwuiN8rNneGut9DUkO9/hfasBlpHp4kkAkvEHjXiR 5wrX/4dVBXaeieAkkT+i78+e5FTz1Y2vdcb4SXvpL9UjbsUFNtGB41l+4TsPv7Yl4Q4I/o jtGh33PAtEKC7nxzharBFN5lTikxP6T1A3O719MnAGFc/kgmSq6WLLI9G+xMBw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1674146183; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=AQh0swIanCssR3rlyr5cq60y9iMeZJZy8kioKjVR4fc=; b=lDnycYeyyDavzYUGJ/HmjcwY0cx5LD16HSEhkQS1A9ldCvwkEes7qBE5mW53KGlb77V1Ad 4vCJ1S+c3LT0IBAg== From: Sebastian Andrzej Siewior To: Hillf Danton Cc: Mel Gorman , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Davidlohr Bueso , linux-mm@kvack.org, LKML Subject: Re: [PATCH v2] locking/rwbase: Prevent indefinite writer starvation Message-ID: References: <20230117083817.togfwc5cy4g67e5r@techsingularity.net> <20230117165021.t5m7c2d6frbbfzig@techsingularity.net> <20230119011538.3247-1-hdanton@sina.com> <20230119135903.3524-1-hdanton@sina.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230119135903.3524-1-hdanton@sina.com> X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023-01-19 21:59:03 [+0800], Hillf Danton wrote: > On Thu, 19 Jan 2023 09:32:22 +0100 Sebastian Andrzej Siewior > > > > As far as Mel's efforts go, I am satisfied so far. > > If not because you can, could you specify why 4ms fails to cure starvation? It does not fail to cure the starvation. I haven't tested it myself but base on Mel's description and the patch it very much looks like it cures the writer starvation. If you don't like the 4ms, it could be 1ms or 40ms - it does not really matter. The 4ms is aligned on the generic implementation which uses the same value. Unless there is strong evidence to use something else I don't see the need to diverse. Sebastian