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 97B40C001E0 for ; Wed, 2 Aug 2023 19:30:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229495AbjHBTa1 (ORCPT ); Wed, 2 Aug 2023 15:30:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39998 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229741AbjHBTaZ (ORCPT ); Wed, 2 Aug 2023 15:30:25 -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 A0CA1123 for ; Wed, 2 Aug 2023 12:30:24 -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 31DB161AB8 for ; Wed, 2 Aug 2023 19:30:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F77BC433C8; Wed, 2 Aug 2023 19:30:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1691004623; bh=YWHIrzBuFXhnh6PUt3BZrL8tvcNe6ScEV1h84d0POTY=; h=Date:To:From:Subject:From; b=GtRWAq/WVVCkFhkGXfNS+smmSx4f/YOiCztUATJrAGL9DoRrgP/AWjEkVoLpaGkbx EKvHJlcKL/vLSojWO31hKiuflanxsUYwLnVs+g6Oxp/YHHDM/pPB0U5D7IepedYc6J DUDzzyyFGIcmaaSLWct9p3xmNra+QYsWZSYG4MV4= Date: Wed, 02 Aug 2023 12:30:22 -0700 To: mm-commits@vger.kernel.org, ziy@nvidia.com, yuzhao@google.com, ying.huang@intel.com, willy@infradead.org, shy828301@gmail.com, nathan@kernel.org, gerald.schaefer@linux.ibm.com, fengwei.yin@intel.com, david@redhat.com, agordeev@linux.ibm.com, ryan.roberts@arm.com, akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-implement-folio_remove_rmap_range.patch removed from -mm tree Message-Id: <20230802193023.7F77BC433C8@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm: implement folio_remove_rmap_range() has been removed from the -mm tree. Its filename was mm-implement-folio_remove_rmap_range.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Ryan Roberts Subject: mm: implement folio_remove_rmap_range() Date: Thu, 27 Jul 2023 15:18:36 +0100 Like page_remove_rmap() but batch-removes the rmap for a range of pages belonging to a folio. This can provide a small speedup due to less manipuation of the various counters. But more crucially, if removing the rmap for all pages of a folio in a batch, there is no need to (spuriously) add it to the deferred split list, which saves significant cost when there is contention for the split queue lock. All contained pages are accounted using the order-0 folio (or base page) scheme. page_remove_rmap() is refactored so that it forwards to folio_remove_rmap_range() for !compound cases, and both functions now share a common epilogue function. The intention here is to avoid duplication of code. Link: https://lkml.kernel.org/r/20230727141837.3386072-3-ryan.roberts@arm.com Signed-off-by: Ryan Roberts Cc: Alexander Gordeev Cc: David Hildenbrand Cc: Gerald Schaefer Cc: Huang, Ying Cc: Matthew Wilcox (Oracle) Cc: Nathan Chancellor Cc: Yang Shi Cc: Yin Fengwei Cc: Yu Zhao Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/rmap.h | 2 mm/rmap.c | 125 +++++++++++++++++++++++++++++++---------- 2 files changed, 97 insertions(+), 30 deletions(-) --- a/include/linux/rmap.h~mm-implement-folio_remove_rmap_range +++ a/include/linux/rmap.h @@ -200,6 +200,8 @@ void page_add_file_rmap(struct page *, s bool compound); void page_remove_rmap(struct page *, struct vm_area_struct *, bool compound); +void folio_remove_rmap_range(struct folio *folio, struct page *page, + int nr, struct vm_area_struct *vma); void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long address, rmap_t flags); --- a/mm/rmap.c~mm-implement-folio_remove_rmap_range +++ a/mm/rmap.c @@ -1348,6 +1348,94 @@ void page_add_file_rmap(struct page *pag } /** + * __remove_rmap_finish - common operations when taking down a mapping. + * @folio: Folio containing all pages taken down. + * @vma: The VM area containing the range. + * @compound: True if pages were taken down from PMD or false if from PTE(s). + * @nr_unmapped: Number of pages within folio that are now unmapped. + * @nr_mapped: Number of pages within folio that are still mapped. + */ +static void __remove_rmap_finish(struct folio *folio, + struct vm_area_struct *vma, bool compound, + int nr_unmapped, int nr_mapped) +{ + enum node_stat_item idx; + + if (nr_unmapped) { + idx = folio_test_anon(folio) ? NR_ANON_MAPPED : NR_FILE_MAPPED; + __lruvec_stat_mod_folio(folio, idx, -nr_unmapped); + + /* + * Queue large anon folio for deferred split if at least one + * page of the folio is unmapped and at least one page is still + * mapped. + */ + if (folio_test_large(folio) && + folio_test_anon(folio) && nr_mapped) + deferred_split_folio(folio); + } + + /* + * It would be tidy to reset folio_test_anon mapping when fully + * unmapped, but that might overwrite a racing page_add_anon_rmap + * which increments mapcount after us but sets mapping before us: + * so leave the reset to free_pages_prepare, and remember that + * it's only reliable while mapped. + */ + + munlock_vma_folio(folio, vma, compound); +} + +/** + * folio_remove_rmap_range - Take down PTE mappings from a range of pages. + * @folio: Folio containing all pages in range. + * @page: First page in range to unmap. + * @nr: Number of pages to unmap. + * @vma: The VM area containing the range. + * + * All pages in the range must belong to the same VMA & folio. They must be + * mapped with PTEs, not a PMD. + * + * Context: Caller holds the pte lock. + */ +void folio_remove_rmap_range(struct folio *folio, struct page *page, + int nr, struct vm_area_struct *vma) +{ + atomic_t *mapped = &folio->_nr_pages_mapped; + int nr_unmapped = 0; + int nr_mapped = 0; + bool last; + + if (unlikely(folio_test_hugetlb(folio))) { + VM_WARN_ON_FOLIO(1, folio); + return; + } + + VM_WARN_ON_ONCE(page < &folio->page || + page + nr > (&folio->page + folio_nr_pages(folio))); + + if (!folio_test_large(folio)) { + /* Is this the page's last map to be removed? */ + last = atomic_add_negative(-1, &page->_mapcount); + nr_unmapped = last; + } else { + for (; nr != 0; nr--, page++) { + /* Is this the page's last map to be removed? */ + last = atomic_add_negative(-1, &page->_mapcount); + if (last) + nr_unmapped++; + } + + /* Pages still mapped if folio mapped entirely */ + nr_mapped = atomic_sub_return_relaxed(nr_unmapped, mapped); + if (nr_mapped >= COMPOUND_MAPPED) + nr_unmapped = 0; + } + + __remove_rmap_finish(folio, vma, false, nr_unmapped, nr_mapped); +} + +/** * page_remove_rmap - take down pte mapping from a page * @page: page to remove mapping from * @vma: the vm area from which the mapping is removed @@ -1373,15 +1461,13 @@ void page_remove_rmap(struct page *page, return; } - /* Is page being unmapped by PTE? Is this its last map to be removed? */ + /* Is page being unmapped by PTE? */ if (likely(!compound)) { - last = atomic_add_negative(-1, &page->_mapcount); - nr = last; - if (last && folio_test_large(folio)) { - nr = atomic_dec_return_relaxed(mapped); - nr = (nr < COMPOUND_MAPPED); - } - } else if (folio_test_pmd_mappable(folio)) { + folio_remove_rmap_range(folio, page, 1, vma); + return; + } + + if (folio_test_pmd_mappable(folio)) { /* That test is redundant: it's for safety or to optimize out */ last = atomic_add_negative(-1, &folio->_entire_mapcount); @@ -1409,29 +1495,8 @@ void page_remove_rmap(struct page *page, idx = NR_FILE_PMDMAPPED; __lruvec_stat_mod_folio(folio, idx, -nr_pmdmapped); } - if (nr) { - idx = folio_test_anon(folio) ? NR_ANON_MAPPED : NR_FILE_MAPPED; - __lruvec_stat_mod_folio(folio, idx, -nr); - - /* - * Queue anon large folio for deferred split if at least one - * page of the folio is unmapped and at least one page - * is still mapped. - */ - if (folio_test_large(folio) && folio_test_anon(folio)) - if (!compound || nr < nr_pmdmapped) - deferred_split_folio(folio); - } - /* - * It would be tidy to reset folio_test_anon mapping when fully - * unmapped, but that might overwrite a racing page_add_anon_rmap - * which increments mapcount after us but sets mapping before us: - * so leave the reset to free_pages_prepare, and remember that - * it's only reliable while mapped. - */ - - munlock_vma_folio(folio, vma, compound); + __remove_rmap_finish(folio, vma, compound, nr, nr_pmdmapped - nr); } /* _ Patches currently in -mm which might be from ryan.roberts@arm.com are selftests-line-buffer-test-programs-stdout.patch selftests-line-buffer-test-programs-stdout-fix.patch selftests-mm-skip-soft-dirty-tests-on-arm64.patch selftests-mm-enable-mrelease_test-for-arm64.patch selftests-mm-fix-thuge-gen-test-bugs.patch selftests-mm-va_high_addr_switch-should-skip-unsupported-arm64-configs.patch selftests-mm-make-migration-test-robust-to-failure.patch selftests-mm-optionally-pass-duration-to-transhuge-stress.patch selftests-mm-run-all-tests-from-run_vmtestssh.patch mm-batch-zap-large-anonymous-folio-pte-mappings.patch