From patchwork Mon Apr 13 12:52:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kirill A. Shutemov" X-Patchwork-Id: 11485525 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 F33DF15AB for ; Mon, 13 Apr 2020 12:52:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BCEE22073E for ; Mon, 13 Apr 2020 12:52:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BCEE22073E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 681FE8E010B; Mon, 13 Apr 2020 08:52:31 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 658F58E010A; Mon, 13 Apr 2020 08:52:31 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 486018E010B; Mon, 13 Apr 2020 08:52:31 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0114.hostedemail.com [216.40.44.114]) by kanga.kvack.org (Postfix) with ESMTP id 2BA6E8E010A for ; Mon, 13 Apr 2020 08:52:31 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id E91D04FE6 for ; Mon, 13 Apr 2020 12:52:30 +0000 (UTC) X-FDA: 76702820460.09.test31_32fab1496d611 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,kirill.shutemov@linux.intel.com,,RULES_HIT:30003:30054:30070,0,RBL:192.55.52.136:@linux.intel.com:.lbl8.mailshell.net-64.95.201.95 62.18.0.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:23,LUA_SUMMARY:none X-HE-Tag: test31_32fab1496d611 X-Filterd-Recvd-Size: 9041 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by imf39.hostedemail.com (Postfix) with ESMTP for ; Mon, 13 Apr 2020 12:52:30 +0000 (UTC) IronPort-SDR: jmjFWbQbZDJQLc+HiP6d37Gci92IU4RzdG009Xqt5jgktAPqZ0dqyfT7giEkAthn2QLhldrME3 5ZLms1UKKvdA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Apr 2020 05:52:28 -0700 IronPort-SDR: 1GdQ/fz3WeapP34bJBOSesvpHCFj8Fo7CxSP8PLrSIA3qA2MP0CL1GvUkAV0yFRB9w7XQ7D/ht TSoQAscxskRQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,378,1580803200"; d="scan'208";a="426678123" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga005.jf.intel.com with ESMTP; 13 Apr 2020 05:52:25 -0700 Received: by black.fi.intel.com (Postfix, from userid 1000) id 02307236; Mon, 13 Apr 2020 15:52:21 +0300 (EEST) From: "Kirill A. Shutemov" To: akpm@linux-foundation.org, Andrea Arcangeli Cc: Zi Yan , Yang Shi , Ralph Campbell , John Hubbard , William Kucharski , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCHv3, RESEND 6/8] khugepaged: Allow to collapse PTE-mapped compound pages Date: Mon, 13 Apr 2020 15:52:18 +0300 Message-Id: <20200413125220.663-7-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200413125220.663-1-kirill.shutemov@linux.intel.com> References: <20200413125220.663-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: We can collapse PTE-mapped compound pages. We only need to avoid handling them more than once: lock/unlock page only once if it's present in the PMD range multiple times as it handled on compound level. The same goes for LRU isolation and putback. Signed-off-by: Kirill A. Shutemov Acked-by: Yang Shi --- mm/khugepaged.c | 99 ++++++++++++++++++++++++++++++++----------------- 1 file changed, 65 insertions(+), 34 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index f9864644c3b7..11d500396d85 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -515,17 +515,30 @@ void __khugepaged_exit(struct mm_struct *mm) static void release_pte_page(struct page *page) { - dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); + mod_node_page_state(page_pgdat(page), + NR_ISOLATED_ANON + page_is_file_cache(page), + -compound_nr(page)); unlock_page(page); putback_lru_page(page); } -static void release_pte_pages(pte_t *pte, pte_t *_pte) +static void release_pte_pages(pte_t *pte, pte_t *_pte, + struct list_head *compound_pagelist) { + struct page *page, *tmp; + while (--_pte >= pte) { pte_t pteval = *_pte; - if (!pte_none(pteval) && !is_zero_pfn(pte_pfn(pteval))) - release_pte_page(pte_page(pteval)); + + page = pte_page(pteval); + if (!pte_none(pteval) && !is_zero_pfn(pte_pfn(pteval)) && + !PageCompound(page)) + release_pte_page(page); + } + + list_for_each_entry_safe(page, tmp, compound_pagelist, lru) { + list_del(&page->lru); + release_pte_page(page); } } @@ -549,7 +562,8 @@ static bool is_refcount_suitable(struct page *page) static int __collapse_huge_page_isolate(struct vm_area_struct *vma, unsigned long address, - pte_t *pte) + pte_t *pte, + struct list_head *compound_pagelist) { struct page *page = NULL; pte_t *_pte; @@ -579,13 +593,21 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, goto out; } - /* TODO: teach khugepaged to collapse THP mapped with pte */ + VM_BUG_ON_PAGE(!PageAnon(page), page); + if (PageCompound(page)) { - result = SCAN_PAGE_COMPOUND; - goto out; - } + struct page *p; + page = compound_head(page); - VM_BUG_ON_PAGE(!PageAnon(page), page); + /* + * Check if we have dealt with the compound page + * already + */ + list_for_each_entry(p, compound_pagelist, lru) { + if (page == p) + goto next; + } + } /* * We can do it before isolate_lru_page because the @@ -614,19 +636,15 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, result = SCAN_PAGE_COUNT; goto out; } - if (pte_write(pteval)) { - writable = true; - } else { - if (PageSwapCache(page) && - !reuse_swap_page(page, NULL)) { - unlock_page(page); - result = SCAN_SWAP_CACHE_PAGE; - goto out; - } + if (!pte_write(pteval) && PageSwapCache(page) && + !reuse_swap_page(page, NULL)) { /* - * Page is not in the swap cache. It can be collapsed - * into a THP. + * Page is in the swap cache and cannot be re-used. + * It cannot be collapsed into a THP. */ + unlock_page(page); + result = SCAN_SWAP_CACHE_PAGE; + goto out; } /* @@ -638,16 +656,23 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, result = SCAN_DEL_PAGE_LRU; goto out; } - inc_node_page_state(page, - NR_ISOLATED_ANON + page_is_file_cache(page)); + mod_node_page_state(page_pgdat(page), + NR_ISOLATED_ANON + page_is_file_cache(page), + compound_nr(page)); VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(PageLRU(page), page); + if (PageCompound(page)) + list_add_tail(&page->lru, compound_pagelist); +next: /* There should be enough young pte to collapse the page */ if (pte_young(pteval) || page_is_young(page) || PageReferenced(page) || mmu_notifier_test_young(vma->vm_mm, address)) referenced++; + + if (pte_write(pteval)) + writable = true; } if (likely(writable)) { if (likely(referenced)) { @@ -661,7 +686,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, } out: - release_pte_pages(pte, _pte); + release_pte_pages(pte, _pte, compound_pagelist); trace_mm_collapse_huge_page_isolate(page, none_or_zero, referenced, writable, result); return 0; @@ -670,13 +695,14 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, static void __collapse_huge_page_copy(pte_t *pte, struct page *page, struct vm_area_struct *vma, unsigned long address, - spinlock_t *ptl) + spinlock_t *ptl, + struct list_head *compound_pagelist) { + struct page *src_page, *tmp; pte_t *_pte; for (_pte = pte; _pte < pte + HPAGE_PMD_NR; _pte++, page++, address += PAGE_SIZE) { pte_t pteval = *_pte; - struct page *src_page; if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { clear_user_highpage(page, address); @@ -696,7 +722,8 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page, } else { src_page = pte_page(pteval); copy_user_highpage(page, src_page, address, vma); - release_pte_page(src_page); + if (!PageCompound(src_page)) + release_pte_page(src_page); /* * ptl mostly unnecessary, but preempt has to * be disabled to update the per-cpu stats @@ -713,6 +740,11 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page, free_page_and_swap_cache(src_page); } } + + list_for_each_entry_safe(src_page, tmp, compound_pagelist, lru) { + list_del(&src_page->lru); + release_pte_page(src_page); + } } static void khugepaged_alloc_sleep(void) @@ -971,6 +1003,7 @@ static void collapse_huge_page(struct mm_struct *mm, struct page **hpage, int node, int referenced, int unmapped) { + LIST_HEAD(compound_pagelist); pmd_t *pmd, _pmd; pte_t *pte; pgtable_t pgtable; @@ -1071,7 +1104,8 @@ static void collapse_huge_page(struct mm_struct *mm, mmu_notifier_invalidate_range_end(&range); spin_lock(pte_ptl); - isolated = __collapse_huge_page_isolate(vma, address, pte); + isolated = __collapse_huge_page_isolate(vma, address, pte, + &compound_pagelist); spin_unlock(pte_ptl); if (unlikely(!isolated)) { @@ -1096,7 +1130,8 @@ static void collapse_huge_page(struct mm_struct *mm, */ anon_vma_unlock_write(vma->anon_vma); - __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl); + __collapse_huge_page_copy(pte, new_page, vma, address, pte_ptl, + &compound_pagelist); pte_unmap(pte); __SetPageUptodate(new_page); pgtable = pmd_pgtable(_pmd); @@ -1193,11 +1228,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, goto out_unmap; } - /* TODO: teach khugepaged to collapse THP mapped with pte */ - if (PageCompound(page)) { - result = SCAN_PAGE_COMPOUND; - goto out_unmap; - } + page = compound_head(page); /* * Record which node the original page is from and save this