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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7B0D6C77B75 for ; Tue, 16 May 2023 08:49:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wJ5bJ4RGsnv9t4ir0snIeE7crjcgdMkT6enPgor46MI=; b=Jfdhhgq8fbvEH7 ZbyLMCYpNL5FpKeuphQF4QQWmouxdB1umDjUrCO2XRlHC4Eh0mDcXiq97eJHL8yMfcPOCW0RLE/HR /iIj1qwu8GuqOHEh1RnD5eNyAsgasvMvyLKMRQ+kH6/3tmEPD/zb2QyrJPA4MA1hm1K8qsqWdUPvC VdAM+NGwUopXTGJS7UQw5rVnl7CcIhZopS681yDJreKUuUIocPwL0iJQ+DthBNzv0v/kPz2KNIJqh DXisbCjG9VVud5kyAKfAfqfxkFBRIZcB8SJyo9XX45Xh5xtYRe8RtoTIKbjA/f/nI/zRGcOo7SdYc 7r3DbgzA8azuUx/QOwlQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pyqML-004vIo-0e; Tue, 16 May 2023 08:48:41 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pyqMI-004vHP-0h for linux-arm-kernel@lists.infradead.org; Tue, 16 May 2023 08:48:39 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=9gKm6hNxnZ/Qorc3xxf+NVLvSWCZn3qdfwRSX3WF/Bk=; b=js0YVStH13cyFq5np19XMzPZfF Dz6MdM4LXI2Hk4GZpLREH+JR/4tYvxRyAMvoQxeiPB9kjyZsCNi8JsBS/IzowgbplfbpczQ9x2/ia XGvm5MLoMNkpvl5IlKMCw+t+9F6ihZSaOMn58xxqR2/x3w52YrfAGIEOsTciraDA5Q76mFicynePN TRwJioLih3OyN8cwpWonG1n104/YHAriRZq/ZeKfZqUfCjxY7C5kk7SWGtBRNkC6W0JQmQcF703Um z+VUxgL5osKR6PInKErS2Qcq7/U2dFld6MhmpC4xDu+X8ROIVhnR0wVXbRVccYLzbblpM7WSdi6V2 +MLEvpzQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:51546) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1pyqMB-0005P9-8q; Tue, 16 May 2023 09:48:31 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1pyqMA-0000fY-HT; Tue, 16 May 2023 09:48:30 +0100 Date: Tue, 16 May 2023 09:48:30 +0100 From: "Russell King (Oracle)" To: Thomas Gleixner Cc: Andrew Morton , linux-mm@kvack.org, Christoph Hellwig , Uladzislau Rezki , Lorenzo Stoakes , Peter Zijlstra , Baoquan He , John Ogness , linux-arm-kernel@lists.infradead.org, Mark Rutland , Marc Zyngier , x86@kernel.org Subject: Re: Excessive TLB flush ranges Message-ID: References: <87a5y5a6kj.ffs@tglx> <87353x9y3l.ffs@tglx> <87zg658fla.ffs@tglx> <87r0rg93z5.ffs@tglx> <87cz308y3s.ffs@tglx> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87cz308y3s.ffs@tglx> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230516_014838_249879_879A487F X-CRM114-Status: GOOD ( 19.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 16, 2023 at 10:44:07AM +0200, Thomas Gleixner wrote: > On Tue, May 16 2023 at 09:19, Russell King wrote: > > On Tue, May 16, 2023 at 08:37:18AM +0200, Thomas Gleixner wrote: > >> void flush_tlb_kernel_vas(struct list_head *list, unsigned int num_entries): > >> > >> So that an architecture can decide whether it's worth to do walk the > >> entries or whether it resorts to a flush all. > > > > Is "num_entries" what an arch would want to use? How would it use that? > > It doesn't tell an arch whether there is a large range of many list > > entries, or a single entry covering a large range. > > Does it matter? > > The total number of entries to flush is what accumulates and at some > architecture specific threshold that becomes more expensive than a full > flush, independent of the range of the individual list entries, no? It depends what you mean by "num_entries" - is that the number of pages to be flushed in total in the range? If so, what does a valid "start" and "end" range passed to __purge_vmap_area_lazy() mean for num_entries - does that go to (end - start) / PAGE_SIZE, or would it still be restricted to the sum of that per list entry? If so, what's the point of passing in "start" and "end" to this function? I'm not familiar with this code... -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel