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=-23.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 5ED86C433E0 for ; Mon, 1 Feb 2021 21:27:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DD69564ECF for ; Mon, 1 Feb 2021 21:27:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD69564ECF Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 472D56B0005; Mon, 1 Feb 2021 16:27:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 422CA6B0006; Mon, 1 Feb 2021 16:27:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 339456B006E; Mon, 1 Feb 2021 16:27:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0245.hostedemail.com [216.40.44.245]) by kanga.kvack.org (Postfix) with ESMTP id 1D6F56B0005 for ; Mon, 1 Feb 2021 16:27:41 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id CDB17362A for ; Mon, 1 Feb 2021 21:27:40 +0000 (UTC) X-FDA: 77770985880.12.waves88_2018553275c5 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin12.hostedemail.com (Postfix) with ESMTP id A33FA1801AC8C for ; Mon, 1 Feb 2021 21:27:40 +0000 (UTC) X-HE-Tag: waves88_2018553275c5 X-Filterd-Recvd-Size: 4789 Received: from mail-pl1-f173.google.com (mail-pl1-f173.google.com [209.85.214.173]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Mon, 1 Feb 2021 21:27:38 +0000 (UTC) Received: by mail-pl1-f173.google.com with SMTP id y10so6523281plk.7 for ; Mon, 01 Feb 2021 13:27:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=2zdbQAonuBlXaYvwXM20t/+hVpPWTDzFS1lpAy2rpGI=; b=QlXIHc70ObVQQMpMbzdk0TRQosUQKUx3AMRR+dRUfh6Q/To7HmgOkMv5Q2OxCWmMfr +S/PUEpZECdU9CzHR6CYqaU7IhQU/yUDiw1tVL3rZ/5Rhn+0Q2xVDeUh0MxI9Do54VEI wskqtlfu4xUPETNmF4qGwMA2ZmLegh+FmcizmeaEDOXlB95M2ocgcg/iRNpEo/SaFjqp LhNKs5+eR3x6NEkbxPTGRCApJvJxYOzoT3TQUXXnmTRf8XdWq8uyV0zdJ2F9nQ9PLuGw VRqeXFPFjygEq3JdnVxrol25XDZ58GF3MAtB1ec0Cww7WmKdyWfQhxRPk8tjLBFiJBv1 7KCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=2zdbQAonuBlXaYvwXM20t/+hVpPWTDzFS1lpAy2rpGI=; b=ZyJOzgxfUjSPQIce7ht78q7gTc8sC28ntqM1qFBlVY/LgsHCI8BNnxHMfhdCKIUI+p EPYqXKrjkXGw6ZSgiYWXonqKfWKRcm/b7W6ai/49es1rduL0CLDWnanWyNnuycMxBT43 S7EmjHs/tyR1VDwzaPdwuCl5AJQyJrHvefjedo/FcifyXdxV+lNTYPN7f3PcFi9TuvVE t5zD/xRJMCIHyRe3e6L6BnBYEOw36N8NzhRDNQf1H+hlfcP/8ras9h5D4YemIG5tp0Lq hVK8FG48xmmy8KyR9p9dc9svSExzUfb76Ly9aFfN++93XZoBAzW0B/mCYM6colHPd5DV 1h+g== X-Gm-Message-State: AOAM531XjI4c9qumpEU8wnkDC1BueY6y+tAHEkU9pM2X438+i1ATwaGO wMaXxyXBCl5Z8v4X88ITfYbWFQ== X-Google-Smtp-Source: ABdhPJzU22mZgFFzNc/VC757dwSCzmDfIjZJvsF9+7Nxj69aM/f9DnUOvpb352Xgm2e9zNRHZc9V3Q== X-Received: by 2002:a17:902:758b:b029:df:d1f6:9af9 with SMTP id j11-20020a170902758bb02900dfd1f69af9mr19620371pll.21.1612214857988; Mon, 01 Feb 2021 13:27:37 -0800 (PST) Received: from [2620:15c:17:3:4a0f:cfff:fe51:6667] ([2620:15c:17:3:4a0f:cfff:fe51:6667]) by smtp.gmail.com with ESMTPSA id l1sm12697812pgt.26.2021.02.01.13.27.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 01 Feb 2021 13:27:37 -0800 (PST) Date: Mon, 1 Feb 2021 13:27:36 -0800 (PST) From: David Rientjes To: Miaohe Lin cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/huge_memory.c: use helper range_in_vma() in __split_huge_p[u|m]d_locked() In-Reply-To: <20210201093259.52798-1-linmiaohe@huawei.com> Message-ID: References: <20210201093259.52798-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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: On Mon, 1 Feb 2021, Miaohe Lin wrote: > The helper range_in_vma() is introduced via commit 017b1660df89 ("mm: > migration: fix migration of huge PMD shared pages"). But we forgot to > use it in __split_huge_pud_locked() and __split_huge_pmd_locked(). > > Signed-off-by: Miaohe Lin > --- > mm/huge_memory.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 987cf5e4cf90..33353a4f95fb 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1959,8 +1959,7 @@ static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, > unsigned long haddr) > { > VM_BUG_ON(haddr & ~HPAGE_PUD_MASK); > - VM_BUG_ON_VMA(vma->vm_start > haddr, vma); > - VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma); > + VM_BUG_ON_VMA(!range_in_vma(vma, haddr, haddr + HPAGE_PUD_SIZE), vma); > VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud)); > > count_vm_event(THP_SPLIT_PUD); > @@ -2039,8 +2038,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, > int i; > > VM_BUG_ON(haddr & ~HPAGE_PMD_MASK); > - VM_BUG_ON_VMA(vma->vm_start > haddr, vma); > - VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma); > + VM_BUG_ON_VMA(!range_in_vma(vma, haddr, haddr + HPAGE_PMD_SIZE), vma); > VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd) > && !pmd_devmap(*pmd)); > This actually loses information, right? Before the patch, we can determine which conditional is failing because we know the line number that the VM_BUG_ON() is happening on. After the patch, we don't know this. I don't think that's crucial, but I'm not sure it makes sense to do this if the only upside is that we removed one total line of code :)