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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49679EB64DD for ; Thu, 20 Jul 2023 17:14:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229533AbjGTROC (ORCPT ); Thu, 20 Jul 2023 13:14:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230290AbjGTROB (ORCPT ); Thu, 20 Jul 2023 13:14:01 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D5E83B3 for ; Thu, 20 Jul 2023 10:13:59 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6B9F561B84 for ; Thu, 20 Jul 2023 17:13:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBCC5C433C7; Thu, 20 Jul 2023 17:13:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1689873238; bh=Rzy3jooMP3AyV/c4zJTDegF7VQ9pmhFtEJ9mCcURw60=; h=Date:To:From:Subject:From; b=XAAehSvQvvs7CTD9vfxsyQZ/g1VJXH2L98gi9SWCldOc+Z1KIE1UA9YZqhbh/nPCM AXxsNKrweaoys3IpR8rmE/I81U9W7szWwNVXJq6MCtkUtgc0+6rnIg7tD9JDIU6SOj fA0K+TZ/r5VFRHbYBRra/02wDSoGhxfdS9EZP7ms= Date: Thu, 20 Jul 2023 10:13:57 -0700 To: mm-commits@vger.kernel.org, ziy@nvidia.com, yuzhao@google.com, ying.huang@intel.com, willy@infradead.org, shy828301@gmail.com, fengwei.yin@intel.com, david@redhat.com, ryan.roberts@arm.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-batch-zap-large-anonymous-folio-pte-mappings.patch added to mm-unstable branch Message-Id: <20230720171358.BBCC5C433C7@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: batch-zap large anonymous folio PTE mappings has been added to the -mm mm-unstable branch. Its filename is mm-batch-zap-large-anonymous-folio-pte-mappings.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-batch-zap-large-anonymous-folio-pte-mappings.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Ryan Roberts Subject: mm: batch-zap large anonymous folio PTE mappings Date: Thu, 20 Jul 2023 12:29:55 +0100 This allows batching the rmap removal with folio_remove_rmap_range(), which means we avoid spuriously adding a partially unmapped folio to the deferred split queue in the common case, which reduces split queue lock contention. Previously each page was removed from the rmap individually with page_remove_rmap(). If the first page belonged to a large folio, this would cause page_remove_rmap() to conclude that the folio was now partially mapped and add the folio to the deferred split queue. But subsequent calls would cause the folio to become fully unmapped, meaning there is no value to adding it to the split queue. Link: https://lkml.kernel.org/r/20230720112955.643283-4-ryan.roberts@arm.com Signed-off-by: Ryan Roberts Cc: David Hildenbrand Cc: Huang, Ying Cc: Matthew Wilcox (Oracle) Cc: Yang Shi Cc: Yin Fengwei Cc: Yu Zhao Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/memory.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) --- a/mm/memory.c~mm-batch-zap-large-anonymous-folio-pte-mappings +++ a/mm/memory.c @@ -1394,6 +1394,94 @@ zap_install_uffd_wp_if_needed(struct vm_ pte_install_uffd_wp_if_needed(vma, addr, pte, pteval); } +static inline unsigned long page_cont_mapped_vaddr(struct page *page, + struct page *anchor, unsigned long anchor_vaddr) +{ + unsigned long offset; + unsigned long vaddr; + + offset = (page_to_pfn(page) - page_to_pfn(anchor)) << PAGE_SHIFT; + vaddr = anchor_vaddr + offset; + + if (anchor > page) { + if (vaddr > anchor_vaddr) + return 0; + } else { + if (vaddr < anchor_vaddr) + return ULONG_MAX; + } + + return vaddr; +} + +static int folio_nr_pages_cont_mapped(struct folio *folio, + struct page *page, pte_t *pte, + unsigned long addr, unsigned long end) +{ + pte_t ptent; + int floops; + int i; + unsigned long pfn; + struct page *folio_end; + + if (!folio_test_large(folio)) + return 1; + + folio_end = &folio->page + folio_nr_pages(folio); + end = min(page_cont_mapped_vaddr(folio_end, page, addr), end); + floops = (end - addr) >> PAGE_SHIFT; + pfn = page_to_pfn(page); + pfn++; + pte++; + + for (i = 1; i < floops; i++) { + ptent = ptep_get(pte); + + if (!pte_present(ptent) || pte_pfn(ptent) != pfn) + break; + + pfn++; + pte++; + } + + return i; +} + +static unsigned long try_zap_anon_pte_range(struct mmu_gather *tlb, + struct vm_area_struct *vma, + struct folio *folio, + struct page *page, pte_t *pte, + unsigned long addr, int nr_pages, + struct zap_details *details) +{ + struct mm_struct *mm = tlb->mm; + pte_t ptent; + bool full; + int i; + + for (i = 0; i < nr_pages;) { + ptent = ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm); + tlb_remove_tlb_entry(tlb, pte, addr); + zap_install_uffd_wp_if_needed(vma, addr, pte, details, ptent); + full = __tlb_remove_page(tlb, page, 0); + + if (unlikely(page_mapcount(page) < 1)) + print_bad_pte(vma, addr, ptent, page); + + i++; + page++; + pte++; + addr += PAGE_SIZE; + + if (unlikely(full)) + break; + } + + folio_remove_rmap_range(folio, page - i, i, vma); + + return i; +} + static unsigned long zap_pte_range(struct mmu_gather *tlb, struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, @@ -1431,6 +1519,38 @@ static unsigned long zap_pte_range(struc page = vm_normal_page(vma, addr, ptent); if (unlikely(!should_zap_page(details, page))) continue; + + /* + * Batch zap large anonymous folio mappings. This allows + * batching the rmap removal, which means we avoid + * spuriously adding a partially unmapped folio to the + * deferrred split queue in the common case, which + * reduces split queue lock contention. + */ + if (page && PageAnon(page)) { + struct folio *folio = page_folio(page); + int nr_pages_req, nr_pages; + + nr_pages_req = folio_nr_pages_cont_mapped( + folio, page, pte, addr, end); + + nr_pages = try_zap_anon_pte_range(tlb, vma, + folio, page, pte, addr, + nr_pages_req, details); + + rss[mm_counter(page)] -= nr_pages; + nr_pages--; + pte += nr_pages; + addr += nr_pages << PAGE_SHIFT; + + if (unlikely(nr_pages < nr_pages_req)) { + force_flush = 1; + addr += PAGE_SIZE; + break; + } + continue; + } + ptent = ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm); tlb_remove_tlb_entry(tlb, pte, addr); _ Patches currently in -mm which might be from ryan.roberts@arm.com are mm-allow-deferred-splitting-of-arbitrary-large-anon-folios.patch mm-implement-folio_remove_rmap_range.patch mm-batch-zap-large-anonymous-folio-pte-mappings.patch