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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8364FC43331 for ; Thu, 2 Apr 2020 04:07:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3B89020747 for ; Thu, 2 Apr 2020 04:07:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="FXV/uL9Q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B89020747 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E2B548E0051; Thu, 2 Apr 2020 00:07:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DDAA58E000D; Thu, 2 Apr 2020 00:07:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CF0828E0051; Thu, 2 Apr 2020 00:07:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0105.hostedemail.com [216.40.44.105]) by kanga.kvack.org (Postfix) with ESMTP id B4F338E000D for ; Thu, 2 Apr 2020 00:07:44 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 75B5C1277 for ; Thu, 2 Apr 2020 04:07:44 +0000 (UTC) X-FDA: 76661581248.20.kite36_438c8f21c6060 X-HE-Tag: kite36_438c8f21c6060 X-Filterd-Recvd-Size: 4205 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Thu, 2 Apr 2020 04:07:44 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 240A62074D; Thu, 2 Apr 2020 04:07:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585800463; bh=aAsEaA5OHvFiUVKHe0ofvAj8R1CmEuc6a500PdqLsYk=; h=Date:From:To:Subject:In-Reply-To:From; b=FXV/uL9QroDrYqfsHgHa/clZh0tmHZRHyg8R1cvaRfMJonOSp54PVTkzm0q7KdUnI tuc+06KjX3k1G5D5yTWKBljv5n2BpFfCXirrLOe4VQ5yYYnfiUITurJstCX0XQY856 PE0sHxliDGGYuvzS9dE19acHacfzaoZ9r9SlaXCc= Date: Wed, 01 Apr 2020 21:07:42 -0700 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, steven.price@arm.com, thellstrom@vmware.com, torvalds@linux-foundation.org Subject: [patch 081/155] mm/mapping_dirty_helpers: update huge page-table entry callbacks Message-ID: <20200402040742.acLv7dgns%akpm@linux-foundation.org> In-Reply-To: <20200401210155.09e3b9742e1c6e732f5a7250@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Thomas Hellstrom Subject: mm/mapping_dirty_helpers: update huge page-table entry callbacks Following the update of pagewalk code commit a07984d48146 ("mm: pagewalk: add p4d_entry() and pgd_entry()") we can modify the mapping_dirty_helpers' huge page-table entry callbacks to avoid splitting when a huge pud or -pmd is encountered. Link: http://lkml.kernel.org/r/20200203154305.15045-1-thomas_os@shipmail.org Signed-off-by: Thomas Hellstrom Reviewed-by: Steven Price Cc: Andrew Morton Signed-off-by: Andrew Morton --- mm/mapping_dirty_helpers.c | 42 +++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-) --- a/mm/mapping_dirty_helpers.c~mm-mapping_dirty_helpers-update-huge-page-table-entry-callbacks +++ a/mm/mapping_dirty_helpers.c @@ -111,26 +111,60 @@ static int clean_record_pte(pte_t *pte, return 0; } -/* wp_clean_pmd_entry - The pagewalk pmd callback. */ +/* + * wp_clean_pmd_entry - The pagewalk pmd callback. + * + * Dirty-tracking should take place on the PTE level, so + * WARN() if encountering a dirty huge pmd. + * Furthermore, never split huge pmds, since that currently + * causes dirty info loss. The pagefault handler should do + * that if needed. + */ static int wp_clean_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long end, struct mm_walk *walk) { - /* Dirty-tracking should be handled on the pte level */ pmd_t pmdval = pmd_read_atomic(pmd); + if (!pmd_trans_unstable(&pmdval)) + return 0; + + if (pmd_none(pmdval)) { + walk->action = ACTION_AGAIN; + return 0; + } + + /* Huge pmd, present or migrated */ + walk->action = ACTION_CONTINUE; if (pmd_trans_huge(pmdval) || pmd_devmap(pmdval)) WARN_ON(pmd_write(pmdval) || pmd_dirty(pmdval)); return 0; } -/* wp_clean_pud_entry - The pagewalk pud callback. */ +/* + * wp_clean_pud_entry - The pagewalk pud callback. + * + * Dirty-tracking should take place on the PTE level, so + * WARN() if encountering a dirty huge puds. + * Furthermore, never split huge puds, since that currently + * causes dirty info loss. The pagefault handler should do + * that if needed. + */ static int wp_clean_pud_entry(pud_t *pud, unsigned long addr, unsigned long end, struct mm_walk *walk) { - /* Dirty-tracking should be handled on the pte level */ pud_t pudval = READ_ONCE(*pud); + if (!pud_trans_unstable(&pudval)) + return 0; + + if (pud_none(pudval)) { + walk->action = ACTION_AGAIN; + return 0; + } + + /* Huge pud */ + walk->action = ACTION_CONTINUE; if (pud_trans_huge(pudval) || pud_devmap(pudval)) WARN_ON(pud_write(pudval) || pud_dirty(pudval)); _