From patchwork Mon Jun 26 17:14:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ryan Roberts X-Patchwork-Id: 13293236 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50F77EB64DC for ; Mon, 26 Jun 2023 17:15:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DFCB98D0001; Mon, 26 Jun 2023 13:15:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D5E3C8E0002; Mon, 26 Jun 2023 13:15:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C27A58D000A; Mon, 26 Jun 2023 13:15:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id B5DB58D0001 for ; Mon, 26 Jun 2023 13:15:05 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 6E0D416068B for ; Mon, 26 Jun 2023 17:15:05 +0000 (UTC) X-FDA: 80945549370.10.8626114 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf15.hostedemail.com (Postfix) with ESMTP id 7B340A000C for ; Mon, 26 Jun 2023 17:15:03 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=none; spf=pass (imf15.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1687799703; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=igZkz1a6pk30y7Cb39JwkU8z+NvNmcA3pvWODxUTXD0=; b=rdAl/Ju7RMQRCRmW9xnjusYVgkm5WNruEseGkUi2xKDFi0dlM54b3kKpNBdX32OSesdUmH Igaa8KN5q6Td0rms/qpcsjcuYB7PEfVQxka9oxh5N9NzyprD1EtroJlk+Db2ZUwh+yFUje eZJXg9c5aRrgyTFhsLf9wu03T2qwg8M= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1687799703; a=rsa-sha256; cv=none; b=pofwEk0lmpMzdvX46qJYcZdLvB+qd1rbf2FHtwTYP0hWG8VVNgRi4FOubVEQ51fmKBrKgB uhEoJivQ9TWp0T0NicXpQXITDTA6UT6Tt6dLGf73BoxKHV6aAf0xL6rxI2lp7c4k2rm3ZA Wn20xTtUsmMRC9IulBXZrRRNYSdcKhA= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=none; spf=pass (imf15.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com; dmarc=pass (policy=none) header.from=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A3C721595; Mon, 26 Jun 2023 10:15:46 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BA1553F663; Mon, 26 Jun 2023 10:14:59 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , "Matthew Wilcox (Oracle)" , "Kirill A. Shutemov" , Yin Fengwei , David Hildenbrand , Yu Zhao , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Christian Borntraeger , Sven Schnelle , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Cc: Ryan Roberts , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-s390@vger.kernel.org Subject: [PATCH v1 07/10] mm: Batch-zap large anonymous folio PTE mappings Date: Mon, 26 Jun 2023 18:14:27 +0100 Message-Id: <20230626171430.3167004-8-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230626171430.3167004-1-ryan.roberts@arm.com> References: <20230626171430.3167004-1-ryan.roberts@arm.com> MIME-Version: 1.0 X-Stat-Signature: kpftabh1jdk85hqom4kx1u5kph7xjbow X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 7B340A000C X-Rspam-User: X-HE-Tag: 1687799703-27496 X-HE-Meta: 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 kRYxBgeM yaFZTrb9+qfnS1CQA/hmqEpRIvrYhu9cPlFwRiaaClV1er7KTusTb0aSYB+I4qK+eCiYdxwN5gX0EhDMlu4AgKy2LCZRgQ9vQPRNZsE3cjCPMxGOfSO24oyyV+zqupjzJ1N9rcpP3A2R64HKmpEduA6OjVA4qX3irLMUG 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: This allows batching the rmap removal with folio_remove_rmap_range(), 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. 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. Signed-off-by: Ryan Roberts --- mm/memory.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index 53896d46e686..9165ed1b9fc2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -914,6 +914,57 @@ copy_present_page(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma return 0; } +static inline unsigned long page_addr(struct page *page, + struct page *anchor, unsigned long anchor_addr) +{ + unsigned long offset; + unsigned long addr; + + offset = (page_to_pfn(page) - page_to_pfn(anchor)) << PAGE_SHIFT; + addr = anchor_addr + offset; + + if (anchor > page) { + if (addr > anchor_addr) + return 0; + } else { + if (addr < anchor_addr) + return ULONG_MAX; + } + + return addr; +} + +static int calc_anon_folio_map_pgcount(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; + + end = min(page_addr(&folio->page + folio_nr_pages(folio), 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) { + return i; + } + + pfn++; + pte++; + } + + return floops; +} + /* * Copy one pte. Returns 0 if succeeded, or -EAGAIN if one preallocated page * is required to copy this pte. @@ -1379,6 +1430,44 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma, pte_install_uffd_wp_if_needed(vma, addr, pte, pteval); } +static unsigned long zap_anon_pte_range(struct mmu_gather *tlb, + struct vm_area_struct *vma, + struct page *page, pte_t *pte, + unsigned long addr, unsigned long end, + bool *full_out) +{ + struct folio *folio = page_folio(page); + struct mm_struct *mm = tlb->mm; + pte_t ptent; + int pgcount; + int i; + bool full; + + pgcount = calc_anon_folio_map_pgcount(folio, page, pte, addr, end); + + for (i = 0; i < pgcount;) { + ptent = ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm); + tlb_remove_tlb_entry(tlb, pte, addr); + 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); + + *full_out = full; + 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, @@ -1415,6 +1504,36 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, 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. Require the VMA + * to be anonymous to ensure that none of the PTEs in + * the range require zap_install_uffd_wp_if_needed(). + */ + if (page && PageAnon(page) && vma_is_anonymous(vma)) { + bool full; + int pgcount; + + pgcount = zap_anon_pte_range(tlb, vma, + page, pte, addr, end, &full); + + rss[mm_counter(page)] -= pgcount; + pgcount--; + pte += pgcount; + addr += pgcount << PAGE_SHIFT; + + if (unlikely(full)) { + 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);