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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60B70EB64DC for ; Wed, 28 Jun 2023 19:19:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231373AbjF1TT2 (ORCPT ); Wed, 28 Jun 2023 15:19:28 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:23168 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230361AbjF1TTY (ORCPT ); Wed, 28 Jun 2023 15:19:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1687979917; 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=z3+WfKV5Wz85M3f84YrJfAbIjSPqDA0LNe6BQbP5oxI=; b=a8lYgvYeh20eA7MBW/kabaWwxEOC6NhP6Eb1GbVnUlM1RzawT+vvmXRl2nUOlkN5twrsXH bh/Kd/2R5aObLnPORHj+o5FJbYcLPUe2rlK2e7iqwMm3o/eA+/1tDw9lEyqTwZSmt3CAAO cNGTBm+1s9/YEFVCL64D4oc9F36KxiI= 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-401-x-1JRoffOwuUYVdkw7tiHQ-1; Wed, 28 Jun 2023 15:18:34 -0400 X-MC-Unique: x-1JRoffOwuUYVdkw7tiHQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5A56F185A7A4; Wed, 28 Jun 2023 19:18:33 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8F7FF46EE28; Wed, 28 Jun 2023 19:18:32 +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: <20230626085035.e66992e96b4c6d37dad54bd9@linux-foundation.org> To: Linus Torvalds Cc: dhowells@redhat.com, Andrew Morton , Stephen Rothwell , linux-mm@kvack.org, mm-commits@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [GIT PULL] MM updates for 6.5-rc1 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3696803.1687979912.1@warthog.procyon.org.uk> Date: Wed, 28 Jun 2023 20:18:32 +0100 Message-ID: <3696804.1687979912@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > Side note: I think we should just do the "FOLL_GET" doesn't touch the > refcount either, which would make this all become just Yeah... but there's a lot of places that would potentially need fixing. iov_iter_get_pages*(), for example, is used to grab pages and push them to all sorts of destinations, including pipes and sk_buffs. > but then we would need to fix try_grab_page() and gup_put_folio() and > friends to match. And any other cases I haven't thought of. And put_page(), folio_put(), ... I wonder if there would be a noticeable performance loss from adding an is_zero_page() check into those. It might also make sense to include the entire kernel post-init static image in that, perhaps a check: if ((unsigned long)(virt_address) & KERNEL_MASK == KERNEL_BASE) return; David