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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 4E4C3C433DF for ; Wed, 24 Jun 2020 09:47:56 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1015620885 for ; Wed, 24 Jun 2020 09:47:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="APKQ4UZ5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1015620885 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A449F6B000A; Wed, 24 Jun 2020 05:47:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A1B9F6B000C; Wed, 24 Jun 2020 05:47:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8E4186B000D; Wed, 24 Jun 2020 05:47:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0225.hostedemail.com [216.40.44.225]) by kanga.kvack.org (Postfix) with ESMTP id 7973F6B000A for ; Wed, 24 Jun 2020 05:47:55 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 41936A2B3 for ; Wed, 24 Jun 2020 09:47:55 +0000 (UTC) X-FDA: 76963628910.29.club16_211498226e43 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 1B26B18086CB6 for ; Wed, 24 Jun 2020 09:47:55 +0000 (UTC) X-HE-Tag: club16_211498226e43 X-Filterd-Recvd-Size: 5796 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Wed, 24 Jun 2020 09:47:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592992074; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZvnIZKhm25nuUcwY++Se/AD4Y/yDm/G3vrwu+upLAu0=; b=APKQ4UZ5362CVgb2NTfIE3wxdrkU+LF3vJ/ykL0HoVlSSsXawfEXl6PEuLzOYNFZ/jW2kU VzKhuiZw4TEG18mxgxBkHGlLPKUtUYrOE1j2s2csuCznvh87X5LilJkuemPtNoLBrvgEhk tXH8vwVq9zeinJZ02aXIIv+0gvhwyZ8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-174-Ww1R_CYKP-eHnVwdx-4e6A-1; Wed, 24 Jun 2020 05:47:52 -0400 X-MC-Unique: Ww1R_CYKP-eHnVwdx-4e6A-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B0E379116D; Wed, 24 Jun 2020 09:47:50 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-65.ams2.redhat.com [10.36.113.65]) by smtp.corp.redhat.com (Postfix) with ESMTP id 34801101E671; Wed, 24 Jun 2020 09:47:48 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Wei Yang , Michal Hocko , Dan Williams , stable@vger.kernel.org, Andrew Morton , Johannes Weiner , Minchan Kim , Huang Ying , Wei Yang , Mel Gorman Subject: [PATCH v3 1/3] mm/shuffle: don't move pages between zones and don't read garbage memmaps Date: Wed, 24 Jun 2020 11:47:39 +0200 Message-Id: <20200624094741.9918-2-david@redhat.com> In-Reply-To: <20200624094741.9918-1-david@redhat.com> References: <20200624094741.9918-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Rspamd-Queue-Id: 1B26B18086CB6 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 Content-Transfer-Encoding: quoted-printable 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: Especially with memory hotplug, we can have offline sections (with a garbage memmap) and overlapping zones. We have to make sure to only touch initialized memmaps (online sections managed by the buddy) and that the zone matches, to not move pages between zones. To test if this can actually happen, I added a simple BUG_ON(page_zone(page_i) !=3D page_zone(page_j)); right before the swap. When hotplugging a 256M DIMM to a 4G x86-64 VM and onlining the first memory block "online_movable" and the second memory block "online_kernel", it will trigger the BUG, as both zones (NORMAL and MOVABLE) overlap. This might result in all kinds of weird situations (e.g., double allocations, list corruptions, unmovable allocations ending up in the movable zone). Fixes: e900a918b098 ("mm: shuffle initial free memory to improve memory-s= ide-cache utilization") Reviewed-by: Wei Yang Acked-by: Michal Hocko Acked-by: Dan Williams Cc: stable@vger.kernel.org # v5.2+ Cc: Andrew Morton Cc: Johannes Weiner Cc: Michal Hocko Cc: Minchan Kim Cc: Huang Ying Cc: Wei Yang Cc: Mel Gorman Signed-off-by: David Hildenbrand --- mm/shuffle.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/mm/shuffle.c b/mm/shuffle.c index 44406d9977c77..dd13ab851b3ee 100644 --- a/mm/shuffle.c +++ b/mm/shuffle.c @@ -58,25 +58,25 @@ module_param_call(shuffle, shuffle_store, shuffle_sho= w, &shuffle_param, 0400); * For two pages to be swapped in the shuffle, they must be free (on a * 'free_area' lru), have the same order, and have the same migratetype. */ -static struct page * __meminit shuffle_valid_page(unsigned long pfn, int= order) +static struct page * __meminit shuffle_valid_page(struct zone *zone, + unsigned long pfn, int order) { - struct page *page; + struct page *page =3D pfn_to_online_page(pfn); =20 /* * Given we're dealing with randomly selected pfns in a zone we * need to ask questions like... */ =20 - /* ...is the pfn even in the memmap? */ - if (!pfn_valid_within(pfn)) + /* ... is the page managed by the buddy? */ + if (!page) return NULL; =20 - /* ...is the pfn in a present section or a hole? */ - if (!pfn_in_present_section(pfn)) + /* ... is the page assigned to the same zone? */ + if (page_zone(page) !=3D zone) return NULL; =20 /* ...is the page free and currently on a free_area list? */ - page =3D pfn_to_page(pfn); if (!PageBuddy(page)) return NULL; =20 @@ -123,7 +123,7 @@ void __meminit __shuffle_zone(struct zone *z) * page_j randomly selected in the span @zone_start_pfn to * @spanned_pages. */ - page_i =3D shuffle_valid_page(i, order); + page_i =3D shuffle_valid_page(z, i, order); if (!page_i) continue; =20 @@ -137,7 +137,7 @@ void __meminit __shuffle_zone(struct zone *z) j =3D z->zone_start_pfn + ALIGN_DOWN(get_random_long() % z->spanned_pages, order_pages); - page_j =3D shuffle_valid_page(j, order); + page_j =3D shuffle_valid_page(z, j, order); if (page_j && page_j !=3D page_i) break; } --=20 2.26.2