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=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A5829C4361B for ; Thu, 17 Dec 2020 02:47:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F3ED23405 for ; Thu, 17 Dec 2020 02:47:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727338AbgLQCrR (ORCPT ); Wed, 16 Dec 2020 21:47:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727262AbgLQCrR (ORCPT ); Wed, 16 Dec 2020 21:47:17 -0500 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A67BFC061794 for ; Wed, 16 Dec 2020 18:46:36 -0800 (PST) Received: by mail-pj1-x1036.google.com with SMTP id l23so3246566pjg.1 for ; Wed, 16 Dec 2020 18:46:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yaotCu5nitXv5Ew++FqWzmZZRyt2uEF7P/i3lpkEgqo=; b=H2pVXOlGlpJGFMGxOpeVjC943QP5s/RMMR9iZT13h+5x6PLcpAzLf3NctLYTo5xj1x O83nwU8Nk8qVmHuXNwjH+ilu7diES4V2+xvo/HN9HSMnbXJqFQfYiHHwo0eijXAqCZz6 vy3Vl8f3ELyeid4LNt5851+EJInwSyo3oLAWuWEg6w1YXYBdldQcN6WhQ0zoo/PD2NLo FC9vs5Q1+sTBpFp7T1dWHGjzwL52jdzegGG7t3tTs8cwQ6kmNnxnOL63nlCGx5ySRf+w +J64Xxb/q+P5HDh6+BMiwsM1MGBQymcPoHCvyhA/V5O94OmUJMI+b9DSpy0+Vuo0aaMC vtqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=yaotCu5nitXv5Ew++FqWzmZZRyt2uEF7P/i3lpkEgqo=; b=qldPGfT8ZSf957pxu7+DMtrcRn0GVcTmj8tWQG6eSNhowm3TVBVFMI/f7DIvNUrTgy Ax6AZXkQQOzOTSGVckPeonwqVxlqP8bqlyBw2fjBp/eS5+coJ3RcHq2MgTEt76dDoJU/ tf2yrsdkjqNwBjGadFgA0qfhpmH2axvhqSfRlwMlDkErmiKytHvaN8CBoU1X69i7HEZk owhhFQ13wPFnk8zryj0Y7KEAkmTie+SiSV5TgStnlI1FF7Ni1QfbG1XiDuZFcIrrdVFO ilg+QrmdFl92U5An8T1clTFs0W0zKS01A2wDOD3wGr4IG8551XrSQ9PJQGu3WZXvKIZi Oodw== X-Gm-Message-State: AOAM530J0qdgOnTj+vW5I19Z6vVnQkDzfh0jeCXmeulR+2lr970owxb3 czEAv2379waQghB8pzjuy9yVcrtdBKrZtBDrCCm2Fg== X-Google-Smtp-Source: ABdhPJzI4l6Nh3E/Rm2+g49nfs4ZjEkjgo1MFpw2whaJMCKO2cnyyWtycDGOxWxNdgtIy3G7Heaw632SCX/a/tz9QAs= X-Received: by 2002:a17:90a:c588:: with SMTP id l8mr5749752pjt.147.1608173195980; Wed, 16 Dec 2020 18:46:35 -0800 (PST) MIME-Version: 1.0 References: <20201213154534.54826-1-songmuchun@bytedance.com> <20201213154534.54826-9-songmuchun@bytedance.com> <20201216144052.GF29394@linux> <20201216221005.GA3207@localhost.localdomain> In-Reply-To: <20201216221005.GA3207@localhost.localdomain> From: Muchun Song Date: Thu, 17 Dec 2020 10:45:59 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v9 08/11] mm/hugetlb: Add a kernel parameter hugetlb_free_vmemmap To: Oscar Salvador Cc: Jonathan Corbet , Mike Kravetz , Thomas Gleixner , mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, Peter Zijlstra , viro@zeniv.linux.org.uk, Andrew Morton , paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, Randy Dunlap , oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, Mina Almasry , David Rientjes , Matthew Wilcox , Michal Hocko , "Song Bao Hua (Barry Song)" , David Hildenbrand , Xiongchun duan , linux-doc@vger.kernel.org, LKML , Linux Memory Management List , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Dec 17, 2020 at 6:10 AM Oscar Salvador wrote: > > On Thu, Dec 17, 2020 at 12:04:11AM +0800, Muchun Song wrote: > > On Wed, Dec 16, 2020 at 10:40 PM Oscar Salvador wrote: > > > > > > On Sun, Dec 13, 2020 at 11:45:31PM +0800, Muchun Song wrote: > > > > Add a kernel parameter hugetlb_free_vmemmap to disable the feature of > > > > freeing unused vmemmap pages associated with each hugetlb page on boot. > > > I guess this should read "to enable the feature"? > > > AFAICS, it is disabled by default. Hi Oscar, Yeah, you are right. It is disabled by default. I forget to update the commit log. Thanks a lot for pointing this out. > > It still would be great to have an answer for that. > > Thanks > > > > > > Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++ > > > > Documentation/admin-guide/mm/hugetlbpage.rst | 3 +++ > > > > arch/x86/mm/init_64.c | 8 ++++++-- > > > > include/linux/hugetlb.h | 19 +++++++++++++++++++ > > > > mm/hugetlb_vmemmap.c | 16 ++++++++++++++++ > > > > 5 files changed, 53 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > > > index 3ae25630a223..9e6854f21d55 100644 > > > > --- a/Documentation/admin-guide/kernel-parameters.txt > > > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > > > @@ -1551,6 +1551,15 @@ > > > > Documentation/admin-guide/mm/hugetlbpage.rst. > > > > Format: size[KMG] > > > > > > > > + hugetlb_free_vmemmap= > > > > + [KNL] When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set, > > > > + this controls freeing unused vmemmap pages associated > > > > + with each HugeTLB page. > > > > + Format: { on | off (default) } > > > > + > > > > + on: enable the feature > > > > + off: disable the feature > > > > + > > > > hung_task_panic= > > > > [KNL] Should the hung task detector generate panics. > > > > Format: 0 | 1 > > > > diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst > > > > index f7b1c7462991..3a23c2377acc 100644 > > > > --- a/Documentation/admin-guide/mm/hugetlbpage.rst > > > > +++ b/Documentation/admin-guide/mm/hugetlbpage.rst > > > > @@ -145,6 +145,9 @@ default_hugepagesz > > > > > > > > will all result in 256 2M huge pages being allocated. Valid default > > > > huge page size is architecture dependent. > > > > +hugetlb_free_vmemmap > > > > + When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set, this enables freeing > > > > + unused vmemmap pages associated with each HugeTLB page. > > > > > > > > When multiple huge page sizes are supported, ``/proc/sys/vm/nr_hugepages`` > > > > indicates the current number of pre-allocated huge pages of the default size. > > > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > > > > index 0435bee2e172..1bce5f20e6ca 100644 > > > > --- a/arch/x86/mm/init_64.c > > > > +++ b/arch/x86/mm/init_64.c > > > > @@ -34,6 +34,7 @@ > > > > #include > > > > #include > > > > #include > > > > +#include > > > > > > > > #include > > > > #include > > > > @@ -1557,7 +1558,8 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, > > > > { > > > > int err; > > > > > > > > - if (end - start < PAGES_PER_SECTION * sizeof(struct page)) > > > > + if (is_hugetlb_free_vmemmap_enabled() || > > > > + end - start < PAGES_PER_SECTION * sizeof(struct page)) > > > > err = vmemmap_populate_basepages(start, end, node, NULL); > > > > else if (boot_cpu_has(X86_FEATURE_PSE)) > > > > err = vmemmap_populate_hugepages(start, end, node, altmap); > > > > @@ -1585,6 +1587,8 @@ void register_page_bootmem_memmap(unsigned long section_nr, > > > > pmd_t *pmd; > > > > unsigned int nr_pmd_pages; > > > > struct page *page; > > > > + bool base_mapping = !boot_cpu_has(X86_FEATURE_PSE) || > > > > + is_hugetlb_free_vmemmap_enabled(); > > > > > > > > for (; addr < end; addr = next) { > > > > pte_t *pte = NULL; > > > > @@ -1610,7 +1614,7 @@ void register_page_bootmem_memmap(unsigned long section_nr, > > > > } > > > > get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO); > > > > > > > > - if (!boot_cpu_has(X86_FEATURE_PSE)) { > > > > + if (base_mapping) { > > > > next = (addr + PAGE_SIZE) & PAGE_MASK; > > > > pmd = pmd_offset(pud, addr); > > > > if (pmd_none(*pmd)) > > > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > > > > index ebca2ef02212..7f47f0eeca3b 100644 > > > > --- a/include/linux/hugetlb.h > > > > +++ b/include/linux/hugetlb.h > > > > @@ -770,6 +770,20 @@ static inline void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, > > > > } > > > > #endif > > > > > > > > +#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP > > > > +extern bool hugetlb_free_vmemmap_enabled; > > > > + > > > > +static inline bool is_hugetlb_free_vmemmap_enabled(void) > > > > +{ > > > > + return hugetlb_free_vmemmap_enabled; > > > > +} > > > > +#else > > > > +static inline bool is_hugetlb_free_vmemmap_enabled(void) > > > > +{ > > > > + return false; > > > > +} > > > > +#endif > > > > + > > > > #else /* CONFIG_HUGETLB_PAGE */ > > > > struct hstate {}; > > > > > > > > @@ -923,6 +937,11 @@ static inline void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr > > > > pte_t *ptep, pte_t pte, unsigned long sz) > > > > { > > > > } > > > > + > > > > +static inline bool is_hugetlb_free_vmemmap_enabled(void) > > > > +{ > > > > + return false; > > > > +} > > > > #endif /* CONFIG_HUGETLB_PAGE */ > > > > > > > > static inline spinlock_t *huge_pte_lock(struct hstate *h, > > > > diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c > > > > index 02201c2e3dfa..64ad929cac61 100644 > > > > --- a/mm/hugetlb_vmemmap.c > > > > +++ b/mm/hugetlb_vmemmap.c > > > > @@ -180,6 +180,22 @@ > > > > #define RESERVE_VMEMMAP_NR 2U > > > > #define RESERVE_VMEMMAP_SIZE (RESERVE_VMEMMAP_NR << PAGE_SHIFT) > > > > > > > > +bool hugetlb_free_vmemmap_enabled; > > > > + > > > > +static int __init early_hugetlb_free_vmemmap_param(char *buf) > > > > +{ > > > > + if (!buf) > > > > + return -EINVAL; > > > > + > > > > + if (!strcmp(buf, "on")) > > > > + hugetlb_free_vmemmap_enabled = true; > > > > + else if (strcmp(buf, "off")) > > > > + return -EINVAL; > > > > + > > > > + return 0; > > > > +} > > > > +early_param("hugetlb_free_vmemmap", early_hugetlb_free_vmemmap_param); > > > > + > > > > static inline unsigned long free_vmemmap_pages_size_per_hpage(struct hstate *h) > > > > { > > > > return (unsigned long)free_vmemmap_pages_per_hpage(h) << PAGE_SHIFT; > > > > -- > > > > 2.11.0 > > > > > > > > > > -- > > > Oscar Salvador > > > SUSE L3 > > > > > > > > -- > > Yours, > > Muchun > > -- > Oscar Salvador > SUSE L3 -- Yours, Muchun