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=-15.6 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 5E173C433E0 for ; Fri, 5 Feb 2021 07:31:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1636D64FB7 for ; Fri, 5 Feb 2021 07:31:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231504AbhBEHbN (ORCPT ); Fri, 5 Feb 2021 02:31:13 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:12467 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231269AbhBEHah (ORCPT ); Fri, 5 Feb 2021 02:30:37 -0500 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4DX6Ts6KNqzjKkV; Fri, 5 Feb 2021 15:28:33 +0800 (CST) Received: from [10.174.179.241] (10.174.179.241) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.498.0; Fri, 5 Feb 2021 15:29:44 +0800 Subject: Re: [PATCH v14 6/8] mm: hugetlb: introduce nr_free_vmemmap_pages in the struct hstate To: Muchun Song CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , References: <20210204035043.36609-1-songmuchun@bytedance.com> <20210204035043.36609-7-songmuchun@bytedance.com> From: Miaohe Lin Message-ID: <42c8272a-f170-b27e-af5e-a7cb7777a728@huawei.com> Date: Fri, 5 Feb 2021 15:29:43 +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: <20210204035043.36609-7-songmuchun@bytedance.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.241] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/2/4 11:50, Muchun Song wrote: > All the infrastructure is ready, so we introduce nr_free_vmemmap_pages > field in the hstate to indicate how many vmemmap pages associated with > a HugeTLB page that can be freed to buddy allocator. And initialize it > in the hugetlb_vmemmap_init(). This patch is actual enablement of the > feature. > > Signed-off-by: Muchun Song > Acked-by: Mike Kravetz > Reviewed-by: Oscar Salvador > --- > include/linux/hugetlb.h | 3 +++ > mm/hugetlb.c | 1 + > mm/hugetlb_vmemmap.c | 30 ++++++++++++++++++++++++++---- > mm/hugetlb_vmemmap.h | 5 +++++ > 4 files changed, 35 insertions(+), 4 deletions(-) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index ad249e56ac49..775aea53669a 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -560,6 +560,9 @@ struct hstate { > unsigned int nr_huge_pages_node[MAX_NUMNODES]; > unsigned int free_huge_pages_node[MAX_NUMNODES]; > unsigned int surplus_huge_pages_node[MAX_NUMNODES]; > +#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP > + unsigned int nr_free_vmemmap_pages; > +#endif > #ifdef CONFIG_CGROUP_HUGETLB > /* cgroup control files */ > struct cftype cgroup_files_dfl[7]; > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 5518283aa667..04dde2b71f3e 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -3220,6 +3220,7 @@ void __init hugetlb_add_hstate(unsigned int order) > h->next_nid_to_free = first_memory_node; > snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", > huge_page_size(h)/1024); > + hugetlb_vmemmap_init(h); > > parsed_hstate = h; > } > diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c > index 224a3cb69bf9..36ebd677e606 100644 > --- a/mm/hugetlb_vmemmap.c > +++ b/mm/hugetlb_vmemmap.c > @@ -208,13 +208,10 @@ early_param("hugetlb_free_vmemmap", early_hugetlb_free_vmemmap_param); > /* > * How many vmemmap pages associated with a HugeTLB page that can be freed > * to the buddy allocator. > - * > - * Todo: Returns zero for now, which means the feature is disabled. We will > - * enable it once all the infrastructure is there. > */ > static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) > { > - return 0; > + return h->nr_free_vmemmap_pages; > } > > static inline unsigned long free_vmemmap_pages_size_per_hpage(struct hstate *h) > @@ -269,3 +266,28 @@ void free_huge_page_vmemmap(struct hstate *h, struct page *head) > */ > vmemmap_remap_free(vmemmap_addr, vmemmap_end, vmemmap_reuse); > } > + > +void __init hugetlb_vmemmap_init(struct hstate *h) > +{ > + unsigned int nr_pages = pages_per_huge_page(h); > + unsigned int vmemmap_pages; > + > + if (!hugetlb_free_vmemmap_enabled) > + return; > + > + vmemmap_pages = (nr_pages * sizeof(struct page)) >> PAGE_SHIFT; > + /* > + * The head page and the first tail page are not to be freed to buddy > + * allocator, the other pages will map to the first tail page, so they > + * can be freed. > + * > + * Could RESERVE_VMEMMAP_NR be greater than @vmemmap_pages? It is true > + * on some architectures (e.g. aarch64). See Documentation/arm64/ > + * hugetlbpage.rst for more details. > + */ > + if (likely(vmemmap_pages > RESERVE_VMEMMAP_NR)) > + h->nr_free_vmemmap_pages = vmemmap_pages - RESERVE_VMEMMAP_NR; Not a problem. Should we set h->nr_free_vmemmap_pages to 0 in 'else' case explicitly ? Anyway, looks good to me. Thanks. Reviewed-by: Miaohe Lin > + > + pr_info("can free %d vmemmap pages for %s\n", h->nr_free_vmemmap_pages, > + h->name); > +} > diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h > index 6f89a9eed02c..02a21604ef1d 100644 > --- a/mm/hugetlb_vmemmap.h > +++ b/mm/hugetlb_vmemmap.h > @@ -14,6 +14,7 @@ > int alloc_huge_page_vmemmap(struct hstate *h, struct page *head, > gfp_t gfp_mask); > void free_huge_page_vmemmap(struct hstate *h, struct page *head); > +void hugetlb_vmemmap_init(struct hstate *h); > #else > static inline int alloc_huge_page_vmemmap(struct hstate *h, struct page *head, > gfp_t gfp_mask) > @@ -24,5 +25,9 @@ static inline int alloc_huge_page_vmemmap(struct hstate *h, struct page *head, > static inline void free_huge_page_vmemmap(struct hstate *h, struct page *head) > { > } > + > +static inline void hugetlb_vmemmap_init(struct hstate *h) > +{ > +} > #endif /* CONFIG_HUGETLB_PAGE_FREE_VMEMMAP */ > #endif /* _LINUX_HUGETLB_VMEMMAP_H */ >