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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 91DB2C433FE for ; Mon, 7 Dec 2020 00:15:34 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 88DE022D08 for ; Mon, 7 Dec 2020 00:15:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 88DE022D08 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=popple.id.au Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4Cq3jv15qkzDqcY for ; Mon, 7 Dec 2020 11:15:31 +1100 (AEDT) Received: from ozlabs.org (bilbo.ozlabs.org [IPv6:2401:3900:2:1::2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Cq3h75Q85zDqPw for ; Mon, 7 Dec 2020 11:13:59 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=popple.id.au Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=popple.id.au header.i=@popple.id.au header.a=rsa-sha256 header.s=202006 header.b=hH5+S65x; dkim-atps=neutral Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4Cq3h66qmfz9sW0; Mon, 7 Dec 2020 11:13:58 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=popple.id.au; s=202006; t=1607300039; bh=kLW1k+REnX3bP/wtpFOvQ2GR20yyvPOKPYd5/ZM/eW0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hH5+S65xSVWTwnhJhgwICAA7vKIpro1ZPn8i75op+bUF1wNVK5vUrYwS7qyk6D4z+ Mh8TKdy63exXo0dv7YcZ9HFOttCSuAi4kYMmaCbU8jx58IC+nWCABQGEXrO6tSILQj iisjd2wmLNkgRtN3IPQzE7p1KHbahj0jK6H1QuNw1oRIWa6VebpcPIJhE+omWEHiWI tqsrzxhii53vP4p70uYx8WtryBKAZLqYpanREnTtySJ2M7ezopW3VzWjFmQfkEndS0 9ofoSeyU9k6GBHOgo4gvm+3Izu4dheRaC3LF5wzt4OOomcRhtY/Hbk/xbCBwLYjnTs bxJn2rkfLJzow== From: Alistair Popple To: Ram Pai Subject: Re: [PATCH] powerpc/book3s_hv_uvmem: Check for failed page migration Date: Mon, 07 Dec 2020 11:13:58 +1100 Message-ID: <3357700.zKBEflIBxY@cleo> In-Reply-To: <20201204165244.GA3390@ram-ibm-com.ibm.com> References: <20201203050812.5234-1-alistair@popple.id.au> <20201204101841.GA621541@in.ibm.com> <20201204165244.GA3390@ram-ibm-com.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, Bharata B Rao Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Saturday, 5 December 2020 3:52:44 AM AEDT Ram Pai wrote: > On Fri, Dec 04, 2020 at 03:48:41PM +0530, Bharata B Rao wrote: > > On Thu, Dec 03, 2020 at 04:08:12PM +1100, Alistair Popple wrote: > This patch certainly looks like the problem, that has been hurting > us for a while. Let me run this patch through my SVM tests. Looks very > promising. > > BTW: The code does a similar thing while paging out. It pages out from the > UV, and then does the migration. Is there a bug there aswell? As specified the migrate_pages_vma() API can fail to migrate device private pages. However the fix was less obvious to me, and in practice I don't think it will ever fail for device private pages as you don't have the same races to establish the page and device private pages can't be pinned. It might be worth adding some kind of warning though in case this ever changes. - Alistair > RP >