Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755057AbbFKPEs (ORCPT ); Thu, 11 Jun 2015 11:04:48 -0400 Received: from mail-lb0-f179.google.com ([209.85.217.179]:35557 "EHLO mail-lb0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752697AbbFKPEp (ORCPT ); Thu, 11 Jun 2015 11:04:45 -0400 MIME-Version: 1.0 In-Reply-To: <1434031637-9091-9-git-send-email-mingo@kernel.org> References: <1434031637-9091-1-git-send-email-mingo@kernel.org> <1434031637-9091-9-git-send-email-mingo@kernel.org> From: Andy Lutomirski Date: Thu, 11 Jun 2015 08:04:23 -0700 Message-ID: Subject: Re: [PATCH 08/12] x86/mm: Remove pgd_list use from vmalloc_sync_all() To: Ingo Molnar Cc: "linux-kernel@vger.kernel.org" , linux-mml@vger.kernel.org, Andrew Morton , Denys Vlasenko , Brian Gerst , Peter Zijlstra , Borislav Petkov , "H. Peter Anvin" , Linus Torvalds , Oleg Nesterov , Thomas Gleixner , Waiman Long Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 947 Lines: 20 On Thu, Jun 11, 2015 at 7:07 AM, Ingo Molnar wrote: > The vmalloc() code uses vmalloc_sync_all() to synchronize changes to > the global reference kernel PGD to task PGDs. Does it? AFAICS the only caller is register_die_notifier, and it's not really clear to me why that exists. At some point I'd love to remove lazy kernel PGD sync from the kernel entirely (or at least from x86) and just do it when we switch mms. Now that you're removing all code that deletes kernel PGD entries, I think all we'd need to do is to add a per-PGD or per-mm count of the number of kernel entries populated and to fix it up when we switch to an mm with fewer entries populated than init_mm. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/