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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 B1185C433E9 for ; Tue, 26 Jan 2021 11:09:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7ED142255F for ; Tue, 26 Jan 2021 11:09:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405038AbhAZLJh (ORCPT ); Tue, 26 Jan 2021 06:09:37 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:11190 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729694AbhAZGly (ORCPT ); Tue, 26 Jan 2021 01:41:54 -0500 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DPxst15TDzl9tD; Tue, 26 Jan 2021 14:39:30 +0800 (CST) Received: from [10.174.179.117] (10.174.179.117) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.498.0; Tue, 26 Jan 2021 14:40:50 +0800 Subject: Re: [PATCH v11 01/13] mm/vmalloc: fix HUGE_VMAP regression by enabling huge pages in vmalloc_to_page To: Nicholas Piggin CC: , , , Jonathan Cameron , Christoph Hellwig , Christophe Leroy , Rick Edgecombe , Ding Tianhong , Christoph Hellwig , Andrew Morton , Linux-MM References: <20210126044510.2491820-1-npiggin@gmail.com> <20210126044510.2491820-2-npiggin@gmail.com> From: Miaohe Lin Message-ID: <76f6c211-c383-51d2-7c5a-575f0d51b82d@huawei.com> Date: Tue, 26 Jan 2021 14:40:50 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210126044510.2491820-2-npiggin@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.117] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi: On 2021/1/26 12:44, Nicholas Piggin wrote: > vmalloc_to_page returns NULL for addresses mapped by larger pages[*]. > Whether or not a vmap is huge depends on the architecture details, > alignments, boot options, etc., which the caller can not be expected > to know. Therefore HUGE_VMAP is a regression for vmalloc_to_page. > > This change teaches vmalloc_to_page about larger pages, and returns > the struct page that corresponds to the offset within the large page. > This makes the API agnostic to mapping implementation details. > > [*] As explained by commit 029c54b095995 ("mm/vmalloc.c: huge-vmap: > fail gracefully on unexpected huge vmap mappings") > > Reviewed-by: Christoph Hellwig > Signed-off-by: Nicholas Piggin > --- > mm/vmalloc.c | 41 ++++++++++++++++++++++++++--------------- > 1 file changed, 26 insertions(+), 15 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index e6f352bf0498..62372f9e0167 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -34,7 +34,7 @@ > #include > #include > #include > - > +#include > #include > #include > #include > @@ -343,7 +343,9 @@ int is_vmalloc_or_module_addr(const void *x) > } > > /* > - * Walk a vmap address to the struct page it maps. > + * Walk a vmap address to the struct page it maps. Huge vmap mappings will > + * return the tail page that corresponds to the base page address, which > + * matches small vmap mappings. > */ > struct page *vmalloc_to_page(const void *vmalloc_addr) > { > @@ -363,25 +365,33 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) > > if (pgd_none(*pgd)) > return NULL; > + if (WARN_ON_ONCE(pgd_leaf(*pgd))) > + return NULL; /* XXX: no allowance for huge pgd */ > + if (WARN_ON_ONCE(pgd_bad(*pgd))) > + return NULL; > + > p4d = p4d_offset(pgd, addr); > if (p4d_none(*p4d)) > return NULL; > - pud = pud_offset(p4d, addr); > + if (p4d_leaf(*p4d)) > + return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT); > + if (WARN_ON_ONCE(p4d_bad(*p4d))) > + return NULL; > > - /* > - * Don't dereference bad PUD or PMD (below) entries. This will also > - * identify huge mappings, which we may encounter on architectures > - * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be > - * identified as vmalloc addresses by is_vmalloc_addr(), but are > - * not [unambiguously] associated with a struct page, so there is > - * no correct value to return for them. > - */ > - WARN_ON_ONCE(pud_bad(*pud)); > - if (pud_none(*pud) || pud_bad(*pud)) > + pud = pud_offset(p4d, addr); > + if (pud_none(*pud)) > + return NULL; > + if (pud_leaf(*pud)) > + return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); > + if (WARN_ON_ONCE(pud_bad(*pud))) > return NULL; > + > pmd = pmd_offset(pud, addr); > - WARN_ON_ONCE(pmd_bad(*pmd)); > - if (pmd_none(*pmd) || pmd_bad(*pmd)) > + if (pmd_none(*pmd)) > + return NULL; > + if (pmd_leaf(*pmd)) > + return pmd_page(*pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); > + if (WARN_ON_ONCE(pmd_bad(*pmd))) > return NULL; > > ptep = pte_offset_map(pmd, addr); > @@ -389,6 +399,7 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) > if (pte_present(pte)) > page = pte_page(pte); > pte_unmap(ptep); > + > return page; > } > EXPORT_SYMBOL(vmalloc_to_page); > LGTM. Thanks. Reviewed-by: Miaohe Lin 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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 993F6C433E6 for ; Tue, 26 Jan 2021 09:55:24 +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 94C9820780 for ; Tue, 26 Jan 2021 09:55:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94C9820780 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com 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 4DQ2Cs229zzDqVs for ; Tue, 26 Jan 2021 20:55:21 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=huawei.com (client-ip=45.249.212.190; helo=szxga04-in.huawei.com; envelope-from=linmiaohe@huawei.com; receiver=) Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4DPxvw3CJhzDqCY for ; Tue, 26 Jan 2021 17:41:08 +1100 (AEDT) Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DPxst15TDzl9tD; Tue, 26 Jan 2021 14:39:30 +0800 (CST) Received: from [10.174.179.117] (10.174.179.117) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.498.0; Tue, 26 Jan 2021 14:40:50 +0800 Subject: Re: [PATCH v11 01/13] mm/vmalloc: fix HUGE_VMAP regression by enabling huge pages in vmalloc_to_page To: Nicholas Piggin References: <20210126044510.2491820-1-npiggin@gmail.com> <20210126044510.2491820-2-npiggin@gmail.com> From: Miaohe Lin Message-ID: <76f6c211-c383-51d2-7c5a-575f0d51b82d@huawei.com> Date: Tue, 26 Jan 2021 14:40:50 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210126044510.2491820-2-npiggin@gmail.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.117] X-CFilter-Loop: Reflected X-Mailman-Approved-At: Tue, 26 Jan 2021 20:53:31 +1100 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: linux-arch@vger.kernel.org, Ding Tianhong , linux-kernel@vger.kernel.org, Christoph Hellwig , Linux-MM , Jonathan Cameron , Andrew Morton , Rick Edgecombe , linuxppc-dev@lists.ozlabs.org, Christoph Hellwig Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi: On 2021/1/26 12:44, Nicholas Piggin wrote: > vmalloc_to_page returns NULL for addresses mapped by larger pages[*]. > Whether or not a vmap is huge depends on the architecture details, > alignments, boot options, etc., which the caller can not be expected > to know. Therefore HUGE_VMAP is a regression for vmalloc_to_page. > > This change teaches vmalloc_to_page about larger pages, and returns > the struct page that corresponds to the offset within the large page. > This makes the API agnostic to mapping implementation details. > > [*] As explained by commit 029c54b095995 ("mm/vmalloc.c: huge-vmap: > fail gracefully on unexpected huge vmap mappings") > > Reviewed-by: Christoph Hellwig > Signed-off-by: Nicholas Piggin > --- > mm/vmalloc.c | 41 ++++++++++++++++++++++++++--------------- > 1 file changed, 26 insertions(+), 15 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index e6f352bf0498..62372f9e0167 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -34,7 +34,7 @@ > #include > #include > #include > - > +#include > #include > #include > #include > @@ -343,7 +343,9 @@ int is_vmalloc_or_module_addr(const void *x) > } > > /* > - * Walk a vmap address to the struct page it maps. > + * Walk a vmap address to the struct page it maps. Huge vmap mappings will > + * return the tail page that corresponds to the base page address, which > + * matches small vmap mappings. > */ > struct page *vmalloc_to_page(const void *vmalloc_addr) > { > @@ -363,25 +365,33 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) > > if (pgd_none(*pgd)) > return NULL; > + if (WARN_ON_ONCE(pgd_leaf(*pgd))) > + return NULL; /* XXX: no allowance for huge pgd */ > + if (WARN_ON_ONCE(pgd_bad(*pgd))) > + return NULL; > + > p4d = p4d_offset(pgd, addr); > if (p4d_none(*p4d)) > return NULL; > - pud = pud_offset(p4d, addr); > + if (p4d_leaf(*p4d)) > + return p4d_page(*p4d) + ((addr & ~P4D_MASK) >> PAGE_SHIFT); > + if (WARN_ON_ONCE(p4d_bad(*p4d))) > + return NULL; > > - /* > - * Don't dereference bad PUD or PMD (below) entries. This will also > - * identify huge mappings, which we may encounter on architectures > - * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be > - * identified as vmalloc addresses by is_vmalloc_addr(), but are > - * not [unambiguously] associated with a struct page, so there is > - * no correct value to return for them. > - */ > - WARN_ON_ONCE(pud_bad(*pud)); > - if (pud_none(*pud) || pud_bad(*pud)) > + pud = pud_offset(p4d, addr); > + if (pud_none(*pud)) > + return NULL; > + if (pud_leaf(*pud)) > + return pud_page(*pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); > + if (WARN_ON_ONCE(pud_bad(*pud))) > return NULL; > + > pmd = pmd_offset(pud, addr); > - WARN_ON_ONCE(pmd_bad(*pmd)); > - if (pmd_none(*pmd) || pmd_bad(*pmd)) > + if (pmd_none(*pmd)) > + return NULL; > + if (pmd_leaf(*pmd)) > + return pmd_page(*pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); > + if (WARN_ON_ONCE(pmd_bad(*pmd))) > return NULL; > > ptep = pte_offset_map(pmd, addr); > @@ -389,6 +399,7 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) > if (pte_present(pte)) > page = pte_page(pte); > pte_unmap(ptep); > + > return page; > } > EXPORT_SYMBOL(vmalloc_to_page); > LGTM. Thanks. Reviewed-by: Miaohe Lin