From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f169.google.com (mail-ig0-f169.google.com [209.85.213.169]) by kanga.kvack.org (Postfix) with ESMTP id 1294F4403D9 for ; Tue, 12 Jan 2016 07:32:54 -0500 (EST) Received: by mail-ig0-f169.google.com with SMTP id z14so124304327igp.1 for ; Tue, 12 Jan 2016 04:32:54 -0800 (PST) Received: from ozlabs.org (ozlabs.org. [2401:3900:2:1::2]) by mx.google.com with ESMTPS id x1si33049728igl.76.2016.01.12.04.32.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Jan 2016 04:32:53 -0800 (PST) In-Reply-To: From: Michael Ellerman Subject: Re: [next] powerpc/mm: fix _PAGE_SWP_SOFT_DIRTY breaking swapoff Message-Id: <20160112123249.98EBF140A98@ozlabs.org> Date: Tue, 12 Jan 2016 23:32:49 +1100 (AEDT) Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins , Laurent Dufour Cc: Cyrill Gorcunov , linux-mm@kvack.org, "Aneesh Kumar K.V" , Martin Schwidefsky , Andrew Morton , linuxppc-dev@lists.ozlabs.org On Sun, 2016-10-01 at 00:54:59 UTC, Hugh Dickins wrote: > Swapoff after swapping hangs on the G5, when CONFIG_CHECKPOINT_RESTORE=y > but CONFIG_MEM_SOFT_DIRTY is not set. That's because the non-zero > _PAGE_SWP_SOFT_DIRTY bit, added by CONFIG_HAVE_ARCH_SOFT_DIRTY=y, is not > discounted when CONFIG_MEM_SOFT_DIRTY is not set: so swap ptes cannot be > recognized. > > (I suspect that the peculiar dependence of HAVE_ARCH_SOFT_DIRTY on > CHECKPOINT_RESTORE in arch/powerpc/Kconfig comes from an incomplete > attempt to solve this problem.) > > It's true that the relationship between CONFIG_HAVE_ARCH_SOFT_DIRTY and > and CONFIG_MEM_SOFT_DIRTY is too confusing, and it's true that swapoff > should be made more robust; but nevertheless, fix up the powerpc ifdefs > as x86_64 and s390 (which met the same problem) have them, defining the > bits as 0 if CONFIG_MEM_SOFT_DIRTY is not set. > > Signed-off-by: Hugh Dickins > Reviewed-by: Cyrill Gorcunov > Acked-by: Laurent Dufour Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/2f10f1a7884e97a68e52c4b6f7 cheers -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org