From patchwork Tue Sep 15 12:59:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muchun Song X-Patchwork-Id: 11776531 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 765B5746 for ; Tue, 15 Sep 2020 13:03:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 50F6A21655 for ; Tue, 15 Sep 2020 13:03:49 +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="iM2XomGq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726605AbgIONDX (ORCPT ); Tue, 15 Sep 2020 09:03:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726578AbgIONCP (ORCPT ); Tue, 15 Sep 2020 09:02:15 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6736C061355 for ; Tue, 15 Sep 2020 06:02:15 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id v14so1674374pjd.4 for ; Tue, 15 Sep 2020 06:02:15 -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=OOFE3ifzi+xdbou1BhqWX71JRgXgTkLEdNFFfTKs9Ws=; b=iM2XomGqOr6vav8SWts2kgwO4r/SIQ083A9ET2quErQScZx633RbxxWH96OcSipOCX etQ478kIKVl/JnnzUUXMu3YnhVVlfmFGIVtMHJq29YxXILuRzbyJ1uFWpeQceXlCD2jY 2C8sffIHvnr9qXcW2LF2qZq5Pch7iEPoKVNf0iQN9oB65y8591n68j7Gx7P9aC+5oy5/ 0fARwEqyJb+m50XkT0C+gNc8xvY+Y6xGbV8aOdsEbsr459+QDdAm/301ctcQiofQjW0B CVN02/XUZPC62uuxxbvHTWp73+iVGDgOgq6+Ou7T5fY9BuvDRNA69A/2fWIPmUNlBxht 6ShA== 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=OOFE3ifzi+xdbou1BhqWX71JRgXgTkLEdNFFfTKs9Ws=; b=HHQtXayCPof+ZThPNPdvnNGYKrE2yG/4PmmNPC6Hkexa5gTyuqUBQ9TNd3JXM4cQzB qbRWHLJZQlhka6p2dO5/7McxGrmXmdxN0aR4qRwkGPoB5Plf6uebD4+7etViHPzjusIc 2ZbwKYUaehotSDwpaZbQNZAYhRwgjRG1ljiSRQrYO9CcWeAZvPjtwyUDbo/wLQbBOm86 yNwcP9vABJzLTg24XDZ3MvFvVk2W12Nh+MTatXyl7w09UfvFWAfpJYiv2hZ0erRZCgql dfLfYaLhp4yuSx+khZb/w/kBlQjRtBzbzTDSOMxr0LU5IK/MPadWNZa5CwchxATwUjar /9Cg== X-Gm-Message-State: AOAM530gcUqBq1cOcJiEdjsLAq4GLu0li7g0Od3GCuGFFbhAMrhyr4yC a5nJIPfguQmt2LDi1EH4jo57oA== X-Google-Smtp-Source: ABdhPJxUfGHzGSJNJof5A7RFUKJlSlo67Ou73YEyK8suZijN2KyyyGZq9MsiZY6eorIYIvYj8Hz5Qw== X-Received: by 2002:a17:90a:d3c2:: with SMTP id d2mr4029408pjw.112.1600174934990; Tue, 15 Sep 2020 06:02:14 -0700 (PDT) Received: from localhost.bytedance.net ([103.136.220.66]) by smtp.gmail.com with ESMTPSA id w185sm14269855pfc.36.2020.09.15.06.02.05 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 15 Sep 2020 06:02:14 -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 Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Muchun Song Subject: [RFC PATCH 13/24] mm/hugetlb: Allocate the vmemmap pages associated with each hugetlb page Date: Tue, 15 Sep 2020 20:59:36 +0800 Message-Id: <20200915125947.26204-14-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20200915125947.26204-1-songmuchun@bytedance.com> References: <20200915125947.26204-1-songmuchun@bytedance.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org When we free a hugetlb page to the buddy, we should allocate the vmemmap pages associated with it. We can do that in the __free_hugepage(). Signed-off-by: Muchun Song --- mm/hugetlb.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6b57a1183785..d0f09fe531fc 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1299,6 +1299,7 @@ static void __free_hugepage(struct hstate *h, struct page *page); #define RESERVE_VMEMMAP_NR 2U #define RESERVE_VMEMMAP_SIZE (RESERVE_VMEMMAP_NR << PAGE_SHIFT) +#define GFP_VMEMMAP_PAGE (GFP_KERNEL | __GFP_NOFAIL | __GFP_MEMALLOC) #define page_huge_pte(page) ((page)->pmd_huge_pte) @@ -1645,6 +1646,107 @@ static void free_huge_page_vmemmap(struct hstate *h, struct page *head) free_vmemmap_page_list(&free_pages); } +static void __remap_huge_page_pte_vmemmap(struct page *reuse, pte_t *ptep, + unsigned long start, + unsigned int nr_remap, + struct list_head *remap_pages) +{ + void *from = (void *)page_private(reuse); + unsigned long addr, end = start + (nr_remap << PAGE_SHIFT); + + for (addr = start; addr < end; addr += PAGE_SIZE) { + void *to; + struct page *page; + pte_t entry, old = *ptep; + + page = list_first_entry_or_null(remap_pages, struct page, lru); + list_del(&page->lru); + to = page_to_virt(page); + copy_page(to, from); + + /* + * Make sure that any data that writes to the @to is made + * visible to the physical page. + */ + flush_kernel_vmap_range(to, PAGE_SIZE); + + prepare_vmemmap_page(page); + + entry = mk_pte(page, PAGE_KERNEL); + set_pte_at(&init_mm, addr, ptep++, entry); + + VM_BUG_ON(!pte_present(old) || pte_page(old) != reuse); + } +} + +static void __remap_huge_page_pmd_vmemmap(struct hstate *h, pmd_t *pmd, + unsigned long addr, + struct list_head *remap_pages) +{ + unsigned long next; + unsigned long start = addr + RESERVE_VMEMMAP_NR * PAGE_SIZE; + unsigned long end = addr + nr_vmemmap_size(h); + struct page *reuse = NULL; + + addr = start; + do { + unsigned int nr_pages; + pte_t *ptep; + + ptep = pte_offset_kernel(pmd, addr); + if (!reuse) { + reuse = pte_page(ptep[-1]); + set_page_private(reuse, addr - PAGE_SIZE); + } + + next = vmemmap_hpage_addr_end(addr, end); + nr_pages = (next - addr) >> PAGE_SHIFT; + __remap_huge_page_pte_vmemmap(reuse, ptep, addr, nr_pages, + remap_pages); + } while (pmd++, addr = next, addr != end); + + flush_tlb_kernel_range(start, end); +} + +static inline void alloc_vmemmap_pages(struct hstate *h, struct list_head *list) +{ + int i; + + for (i = 0; i < nr_free_vmemmap(h); i++) { + struct page *page; + + /* This should not fail */ + page = alloc_page(GFP_VMEMMAP_PAGE); + list_add_tail(&page->lru, list); + } +} + +static void alloc_huge_page_vmemmap(struct hstate *h, struct page *head) +{ + pmd_t *pmd; + spinlock_t *ptl; + LIST_HEAD(remap_pages); + + if (!nr_free_vmemmap(h)) + return; + + alloc_vmemmap_pages(h, &remap_pages); + + pmd = vmemmap_to_pmd(head); + ptl = vmemmap_pmd_lockptr(pmd); + + spin_lock(ptl); + __remap_huge_page_pmd_vmemmap(h, pmd, (unsigned long)head, + &remap_pages); + if (!freed_vmemmap_hpage_dec(pmd_page(*pmd))) { + /* + * Todo: + * Merge pte to huge pmd if it has ever been split. + */ + } + spin_unlock(ptl); +} + /* * As update_and_free_page() is be called from a non-task context(and hold * hugetlb_lock), we can defer the actual freeing in a workqueue to prevent @@ -1720,6 +1822,10 @@ static inline void free_huge_page_vmemmap(struct hstate *h, struct page *head) { } +static inline void alloc_huge_page_vmemmap(struct hstate *h, struct page *head) +{ +} + static inline void __update_and_free_page(struct hstate *h, struct page *page) { __free_hugepage(h, page); @@ -1752,6 +1858,8 @@ static void __free_hugepage(struct hstate *h, struct page *page) { int i; + alloc_huge_page_vmemmap(h, page); + for (i = 0; i < pages_per_huge_page(h); i++) { page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 1 << PG_dirty |