From patchwork Mon Oct 26 14:51:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muchun Song X-Patchwork-Id: 11857505 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4BA026A2 for ; Mon, 26 Oct 2020 14:55:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D1D42463C for ; Mon, 26 Oct 2020 14:55:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=bytedance-com.20150623.gappssmtp.com header.i=@bytedance-com.20150623.gappssmtp.com header.b="deY/yV0J" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1782719AbgJZOzy (ORCPT ); Mon, 26 Oct 2020 10:55:54 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:40344 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1782136AbgJZOzy (ORCPT ); Mon, 26 Oct 2020 10:55:54 -0400 Received: by mail-pf1-f195.google.com with SMTP id w21so6317029pfc.7 for ; Mon, 26 Oct 2020 07:55:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=zKqFfBrPPNmfHuJAiL+mzNtDXNprI4LFbnvEVHi51k0=; b=deY/yV0JSi4ghS+MYfvehuTghmP/k3wU5P7MfbaKSuvybxlaavkj7gxOy9N9od7djU ZDXVA/cCElyyL/7i1bVz1s8klImmDxE+YfdU/8MgNpbTcSa55QU9L/iGFQ0EgvvndVnD 5GrN9vGE76ReMR8URaepwTgpte1Vy+rHJvh2xLeTunn21rpBVscx+0hbH7oQIksHdDRE bLzCTvXoR9XgVqDmYV+HzNCAgK4tFZ9s7uNuecN8KyaFzQCMmF32ZXFEFcBw16eFIvY+ Izc44NYxBcBsP3NqBMx8l/ER+VHQg6oKGRPM5WQp0yimoiCch7CBX++iUV6fdrj2nyeE 7Hdw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=zKqFfBrPPNmfHuJAiL+mzNtDXNprI4LFbnvEVHi51k0=; b=K1jPtaqf+JalsG2m+b5Xy4FZHV6yT4IUgeUHm725eaZG6LLU7CWeyn/3kk82s/PmMS Lqa1wG2G+x9qZ3wqeAR7GqsY1Ig9nDy7FFYekborhVZYQfCleCOXoUAbI08ATHWUvhPf tqGFeuYsMxRQ7ZG4KHcxFnhqfsGJQHSJ1rI4Pv/VUXND3DKmUUJF+2v1FvLrUkCnsNAR 1gQ63i9wQ6GayTzk90PXcMEmFH0IIRMbdEZuxpm6dv6z7ZortY1mZQ2bKpHmcjNndLQL 7vFUiQkuyM8J3Z9C5i3HS882w+yxZ9B2CqMaWmgAMpQDM2zKOqB5mQ0b8QYnFNtMtK49 57WA== X-Gm-Message-State: AOAM53153Ixi/P7GZDch+kA444H/SKN7d5hH73UMY0cnZEw17rayyJuA XsVNWs/9EX8AhaiiByJyqmKtbw== X-Google-Smtp-Source: ABdhPJwZpN31AOXioEN9JiSwqRoUmQ80iiNHv4T0NpDl7YUZ0tnKsoQQevQKz/UeP9vjrxIDoY6Skg== X-Received: by 2002:a63:d650:: with SMTP id d16mr13453163pgj.277.1603724153485; Mon, 26 Oct 2020 07:55:53 -0700 (PDT) Received: from localhost.localdomain ([103.136.220.89]) by smtp.gmail.com with ESMTPSA id x123sm12042726pfb.212.2020.10.26.07.55.44 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Oct 2020 07:55:52 -0700 (PDT) From: Muchun Song To: corbet@lwn.net, mike.kravetz@oracle.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, paulmck@kernel.org, mchehab+huawei@kernel.org, pawan.kumar.gupta@linux.intel.com, rdunlap@infradead.org, oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de, almasrymina@google.com, rientjes@google.com, willy@infradead.org Cc: duanxiongchun@bytedance.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Muchun Song Subject: [PATCH v2 17/19] mm/hugetlb: Merge pte to huge pmd only for gigantic page Date: Mon, 26 Oct 2020 22:51:12 +0800 Message-Id: <20201026145114.59424-18-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20201026145114.59424-1-songmuchun@bytedance.com> References: <20201026145114.59424-1-songmuchun@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Merge pte to huge pmd if it has ever been split. Now only support gigantic page which's vmemmap pages size is an integer multiple of PMD_SIZE. This is the simplest case to handle. Signed-off-by: Muchun Song --- arch/x86/include/asm/hugetlb.h | 8 +++ include/linux/hugetlb.h | 7 +++ mm/hugetlb.c | 106 ++++++++++++++++++++++++++++++++- 3 files changed, 119 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h index 7c3eb60c2198..9f9e19dd0578 100644 --- a/arch/x86/include/asm/hugetlb.h +++ b/arch/x86/include/asm/hugetlb.h @@ -15,6 +15,14 @@ static inline bool vmemmap_pmd_huge(pmd_t *pmd) { return pmd_large(*pmd); } + +#define vmemmap_pmd_mkhuge vmemmap_pmd_mkhuge +static inline pmd_t vmemmap_pmd_mkhuge(struct page *page) +{ + pte_t entry = pfn_pte(page_to_pfn(page), PAGE_KERNEL_LARGE); + + return __pmd(pte_val(entry)); +} #endif #define hugepages_supported() boot_cpu_has(X86_FEATURE_PSE) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 695d3041ae7d..3a45199cc5c1 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -611,6 +611,13 @@ static inline bool vmemmap_pmd_huge(pmd_t *pmd) } #endif +#ifndef vmemmap_pmd_mkhuge +static inline pmd_t vmemmap_pmd_mkhuge(struct page *page) +{ + return pmd_mkhuge(mk_pmd(page, PAGE_KERNEL)); +} +#endif + #ifndef VMEMMAP_HPAGE_SHIFT #define VMEMMAP_HPAGE_SHIFT PMD_SHIFT #endif diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 82467d573fee..a526bcdb137b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1718,6 +1718,62 @@ static void __remap_huge_page_pte_vmemmap(struct page *reuse, pte_t *ptep, } } +static void __replace_huge_page_pte_vmemmap(pte_t *ptep, unsigned long start, + unsigned int nr, struct page *huge, + struct list_head *free_pages) +{ + unsigned long addr; + unsigned long end = start + (nr << PAGE_SHIFT); + + for (addr = start; addr < end; addr += PAGE_SIZE, ptep++) { + struct page *page; + pte_t old = *ptep; + pte_t entry; + + prepare_vmemmap_page(huge); + + entry = mk_pte(huge++, PAGE_KERNEL); + VM_WARN_ON(!pte_present(old)); + page = pte_page(old); + list_add(&page->lru, free_pages); + + set_pte_at(&init_mm, addr, ptep, entry); + } +} + +static void replace_huge_page_pmd_vmemmap(pmd_t *pmd, unsigned long start, + struct page *huge, + struct list_head *free_pages) +{ + unsigned long end = start + VMEMMAP_HPAGE_SIZE; + + flush_cache_vunmap(start, end); + __replace_huge_page_pte_vmemmap(pte_offset_kernel(pmd, start), start, + VMEMMAP_HPAGE_NR, huge, free_pages); + flush_tlb_kernel_range(start, end); +} + +static pte_t *merge_vmemmap_pte(pmd_t *pmdp, unsigned long addr) +{ + pte_t *pte; + struct page *page; + + pte = pte_offset_kernel(pmdp, addr); + page = pte_page(*pte); + set_pmd(pmdp, vmemmap_pmd_mkhuge(page)); + + return pte; +} + +static void merge_huge_page_pmd_vmemmap(pmd_t *pmd, unsigned long start, + struct page *huge, + struct list_head *free_pages) +{ + replace_huge_page_pmd_vmemmap(pmd, start, huge, free_pages); + pte_free_kernel(&init_mm, merge_vmemmap_pte(pmd, start)); + flush_tlb_kernel_range(start, start + VMEMMAP_HPAGE_SIZE); +} + static inline void alloc_vmemmap_pages(struct hstate *h, struct list_head *list) { int i; @@ -1731,6 +1787,15 @@ static inline void alloc_vmemmap_pages(struct hstate *h, struct list_head *list) } } +static inline void dissolve_compound_page(struct page *page, unsigned int order) +{ + int i; + unsigned int nr_pages = 1 << order; + + for (i = 1; i < nr_pages; i++) + set_page_refcounted(page + i); +} + static void alloc_huge_page_vmemmap(struct hstate *h, struct page *head) { pmd_t *pmd; @@ -1750,10 +1815,47 @@ static void alloc_huge_page_vmemmap(struct hstate *h, struct page *head) __remap_huge_page_pte_vmemmap); if (!freed_vmemmap_hpage_dec(pmd_page(*pmd)) && pmd_split(pmd)) { /* - * Todo: - * Merge pte to huge pmd if it has ever been split. + * Merge pte to huge pmd if it has ever been split. Now only + * support gigantic page which's vmemmap pages size is an + * integer multiple of PMD_SIZE. This is the simplest case + * to handle. */ clear_pmd_split(pmd); + + if (IS_ALIGNED(nr_vmemmap(h), VMEMMAP_HPAGE_NR)) { + unsigned long addr = (unsigned long)head; + unsigned long end = addr + nr_vmemmap_size(h); + + spin_unlock(ptl); + + for (; addr < end; addr += VMEMMAP_HPAGE_SIZE) { + void *to; + struct page *page; + + page = alloc_pages(GFP_VMEMMAP_PAGE & ~__GFP_NOFAIL, + VMEMMAP_HPAGE_ORDER); + dissolve_compound_page(page, + VMEMMAP_HPAGE_ORDER); + if (!page) + goto out; + + to = page_to_virt(page); + memcpy(to, (void *)addr, VMEMMAP_HPAGE_SIZE); + + /* + * Make sure that any data that writes to the + * @to is made visible to the physical page. + */ + flush_kernel_vmap_range(to, VMEMMAP_HPAGE_SIZE); + + merge_huge_page_pmd_vmemmap(pmd++, addr, page, + &remap_pages); + } + +out: + free_vmemmap_page_list(&remap_pages); + return; + } } spin_unlock(ptl); }