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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86911EDEC49 for ; Wed, 13 Sep 2023 12:52:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240643AbjIMMwO (ORCPT ); Wed, 13 Sep 2023 08:52:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238125AbjIMMwN (ORCPT ); Wed, 13 Sep 2023 08:52:13 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id C783219B6 for ; Wed, 13 Sep 2023 05:51:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694609482; 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=fcwyuEyPhUjibl+UPXTZ+YZfX1YncqC+LcRBkk4rhVQ=; b=TcwgLUjcSt8KyaNcTRWSDsebjVmcB6IeEn6C4e003MHugNCvu3vXw0ws9oc7VOC1GX3vBX o77ublDLqWL9ARchHN3xVKGkmgiQO2kIXkbKaRnvIPvzWf4wrB/qClW/X8GXKQhcwyRzJq k6Zkr9k2rXm+yT7JH2Z7hSE/AUiJ+Zc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-664-skkLD7dfNDCSC0zIh01gyA-1; Wed, 13 Sep 2023 08:51:19 -0400 X-MC-Unique: skkLD7dfNDCSC0zIh01gyA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3CA79857A9A; Wed, 13 Sep 2023 12:51:19 +0000 (UTC) Received: from t14s.fritz.box (unknown [10.39.193.225]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8FF2D2156721; Wed, 13 Sep 2023 12:51:17 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Andrew Morton , Mike Kravetz , Muchun Song Subject: [PATCH v1 1/6] mm/rmap: drop stale comment in page_add_anon_rmap and hugepage_add_anon_rmap() Date: Wed, 13 Sep 2023 14:51:08 +0200 Message-ID: <20230913125113.313322-2-david@redhat.com> In-Reply-To: <20230913125113.313322-1-david@redhat.com> References: <20230913125113.313322-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org That comment was added in commit 5dbe0af47f8a ("mm: fix kernel BUG at mm/rmap.c:1017!") to document why we can see vma->vm_end getting adjusted concurrently due to a VMA split. However, the optimized locking code was changed again in bf181b9f9d8 ("mm anon rmap: replace same_anon_vma linked list with an interval tree."). ... and later, the comment was changed in commit 0503ea8f5ba7 ("mm/mmap: remove __vma_adjust()") to talk about "vma_merge" although the original issue was with VMA splitting. Let's just remove that comment. Nowadays, it's outdated, imprecise and confusing. Signed-off-by: David Hildenbrand --- mm/rmap.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index ec7f8e6c9e48..ca2787c1fe05 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1245,7 +1245,6 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma, __lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr); if (likely(!folio_test_ksm(folio))) { - /* address might be in next vma when migration races vma_merge */ if (first) __page_set_anon_rmap(folio, page, vma, address, !!(flags & RMAP_EXCLUSIVE)); @@ -2536,7 +2535,6 @@ void hugepage_add_anon_rmap(struct page *page, struct vm_area_struct *vma, BUG_ON(!folio_test_locked(folio)); BUG_ON(!anon_vma); - /* address might be in next vma when migration races vma_merge */ first = atomic_inc_and_test(&folio->_entire_mapcount); VM_BUG_ON_PAGE(!first && (flags & RMAP_EXCLUSIVE), page); VM_BUG_ON_PAGE(!first && PageAnonExclusive(page), page); -- 2.41.0