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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 0769FC4338F for ; Thu, 19 Aug 2021 07:58:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB9B56113A for ; Thu, 19 Aug 2021 07:58:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235052AbhHSH70 (ORCPT ); Thu, 19 Aug 2021 03:59:26 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:52478 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231909AbhHSH7Z (ORCPT ); Thu, 19 Aug 2021 03:59:25 -0400 Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 1CEB5220AB; Thu, 19 Aug 2021 07:58:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1629359929; h=from:from:reply-to: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=GasiM7Gy5clKgsCGkYZlWv0QVHBzwTvldYtpCJdLXlY=; b=F/EtMP5KGs1HWPLA29hG+3PQYkUbvNF6FWEBiwDZc2Z2AJJGG0g/5m5ndZe2yxr93HAWuj yBcCD/txDvEp7IqUcLhalILcKdFnQjyT8heCgiJ4jeRmirL2Yt4o3Tvh91z/5ZKGKbaacK 9HrQ2hO7xm07IbVAyNB3dA/O36Fm7Q8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1629359929; h=from:from:reply-to: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=GasiM7Gy5clKgsCGkYZlWv0QVHBzwTvldYtpCJdLXlY=; b=CNSD3tLSPcXd5p99d1UpO7Ehx9Mu3IroRkaLNmapediVk8MBqEHzK4lOYu72geIGzEPPIU DDZw6mtXroOYG5AQ== Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap1.suse-dmz.suse.de (Postfix) with ESMTPS id 97E57136DD; Thu, 19 Aug 2021 07:58:48 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id aGpJIzgPHmFyEAAAGKfGzw (envelope-from ); Thu, 19 Aug 2021 07:58:48 +0000 Date: Thu, 19 Aug 2021 09:58:46 +0200 From: Joerg Roedel To: Peilin Ye Cc: Andrew Morton , x86@kernel.org, Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Muchun Song , Cong Wang , Peilin Ye Subject: Re: [PATCH RESEND v2] docs: x86: Remove obsolete information about x86_64 vmalloc() faulting Message-ID: References: <20210818220123.2623-1-yepeilin.cs@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210818220123.2623-1-yepeilin.cs@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Wed, Aug 18, 2021 at 03:01:23PM -0700, Peilin Ye wrote: > From: Peilin Ye > > x86_64 vmalloc() mappings are no longer "synchronized" among page tables > via faulting since commit 6eb82f994026 ("x86/mm: Pre-allocate P4D/PUD > pages for vmalloc area"), since the corresponding P4D or PUD pages are > now preallocated at boot, by preallocate_vmalloc_pages(). Drop the > "lazily synchronized" description for less confusion. > > While this file is x86_64-specific, it is worth noting that things are > different for x86_32, where vmalloc()-related changes to `init_mm.pgd` are > synchronized to all page tables in the system during runtime, via > arch_sync_kernel_mappings(). Unfortunately, this synchronization is > subject to race condition, which is further handled via faulting, see > vmalloc_fault(). See commit 4819e15f740e ("x86/mm/32: Bring back vmalloc > faulting on x86_32") for more details. > > Reviewed-by: Muchun Song > Signed-off-by: Peilin Ye Reviewed-by: Joerg Roedel > --- > Hi all, > > Resending this with Muchun's Reviewed-by:. > > Thanks, > Peilin Ye > > Changes in v2: > - More information for x86_32 in commit message (Joerg Roedel > ) > - Use my new email address for work > > Documentation/x86/x86_64/mm.rst | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/Documentation/x86/x86_64/mm.rst b/Documentation/x86/x86_64/mm.rst > index ede1875719fb..9798676bb0bf 100644 > --- a/Documentation/x86/x86_64/mm.rst > +++ b/Documentation/x86/x86_64/mm.rst > @@ -140,10 +140,6 @@ The direct mapping covers all memory in the system up to the highest > memory address (this means in some cases it can also include PCI memory > holes). > > -vmalloc space is lazily synchronized into the different PML4/PML5 pages of > -the processes using the page fault handler, with init_top_pgt as > -reference. > - > We map EFI runtime services in the 'efi_pgd' PGD in a 64Gb large virtual > memory window (this size is arbitrary, it can be raised later if needed). > The mappings are not part of any other kernel PGD and are only available > -- > 2.20.1 >