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 350F4C54EAA for ; Mon, 30 Jan 2023 22:13:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231221AbjA3WNe (ORCPT ); Mon, 30 Jan 2023 17:13:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229889AbjA3WNc (ORCPT ); Mon, 30 Jan 2023 17:13:32 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0779B4A1F2 for ; Mon, 30 Jan 2023 14:12:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1675116747; 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=f/esCj1MNnOe1fnqJrap230ikN63PqOGL5vL8Wutmq8=; b=UYZw6yzXQOUEkZVMRyBG+K162S/l9Enxh3NbDnvaW+TqEI4ZffGXW3IAm0fb844qDzND6s xcVOuJD2N0y+SseFsjSCeWP8Z//MFX/+WpZggAKu4v8H7faW1WeARQsxES/xzgHLNAd+Pk IcohUZmOyasTMhnM+Q93KFXwUyNKMAY= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-568-O5GrhKaEPI-knDkSOqp-UQ-1; Mon, 30 Jan 2023 17:12:23 -0500 X-MC-Unique: O5GrhKaEPI-knDkSOqp-UQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6D10A882822; Mon, 30 Jan 2023 22:12:22 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id ABC721121314; Mon, 30 Jan 2023 22:12:20 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <3351099.1675077249@warthog.procyon.org.uk> To: John Hubbard Cc: dhowells@redhat.com, Jens Axboe , Al Viro , Christoph Hellwig , Matthew Wilcox , Jan Kara , "David Hildenbrand" , Jason Gunthorpe , "Logan Gunthorpe" , Jeff Layton , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [GIT PULL] iov_iter: Improve page extraction (pin or just list) MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3520517.1675116740.1@warthog.procyon.org.uk> Date: Mon, 30 Jan 2023 22:12:20 +0000 Message-ID: <3520518.1675116740@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org John Hubbard wrote: > This is something that we say when adding pin_user_pages_fast(), > yes. I doubt that I can quickly find the email thread, but we > measured it and weren't immediately able to come up with a way > to make it faster. percpu counters maybe - add them up at the point of viewing? David