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[2620:137:e000::1:20]) by mx.google.com with ESMTP id cm24-20020a17090afa1800b00213587b200esi13312552pjb.189.2022.11.08.09.48.43; Tue, 08 Nov 2022 09:48:56 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=Z1hU8eX+; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234639AbiKHRsK (ORCPT + 99 others); Tue, 8 Nov 2022 12:48:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44354 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234466AbiKHRsH (ORCPT ); Tue, 8 Nov 2022 12:48:07 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04D7554B11 for ; Tue, 8 Nov 2022 09:47:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667929627; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=ZHIUqQjgTcrrLQjjH6jvIopGCgDdzoOnD2NdhMSGVIY=; b=Z1hU8eX+m0+4PXmv0GhcuKVspAQUJ/En2WzlLhYl0FSPXsxiUtl8QOrpnQfyKV/hgCgIfP 7gpFmnA/Tf761bhd5YRoo8PMbaePfklZ6ezzbyq8y0AtdMwSS0P1hJ3bU8dM4uSqtBCtL0 F9C4vNEN+eBwCBaZh6BjRm43sKKnajA= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-392-mHodWVn8NdeSar_igPbYsg-1; Tue, 08 Nov 2022 12:46:58 -0500 X-MC-Unique: mHodWVn8NdeSar_igPbYsg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5F17B382F649; Tue, 8 Nov 2022 17:46:57 +0000 (UTC) Received: from t480s.fritz.box (unknown [10.39.194.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8E65DC15BB5; Tue, 8 Nov 2022 17:46:53 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, David Hildenbrand , Linus Torvalds , Andrew Morton , Mel Gorman , Dave Chinner , Nadav Amit , Peter Xu , Andrea Arcangeli , Hugh Dickins , Vlastimil Babka , Michael Ellerman , Nicholas Piggin , Mike Rapoport , Anshuman Khandual Subject: [PATCH v2 0/7] mm/autonuma: replace savedwrite infrastructure Date: Tue, 8 Nov 2022 18:46:45 +0100 Message-Id: <20221108174652.198904-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1748951091797311851?= X-GMAIL-MSGID: =?utf-8?q?1748951091797311851?= This series is based on mm-unstable. As discussed in my talk at LPC, we can reuse the same mechanism for deciding whether to map a pte writable when upgrading permissions via mprotect() -- e.g., PROT_READ -> PROT_READ|PROT_WRITE -- to replace the savedwrite infrastructure used for NUMA hinting faults (e.g., PROT_NONE -> PROT_READ|PROT_WRITE). Instead of maintaining previous write permissions for a pte/pmd, we re-determine if the pte/pmd can be writable. The big benefit is that we have a common logic for deciding whether we can map a pte/pmd writable on protection changes. For private mappings, there should be no difference -- from what I understand, that is what autonuma benchmarks care about. I ran autonumabench for v1 on a system with 2 NUMA nodes, 96 GiB each via: perf stat --null --repeat 10 The numa01 benchmark is quite noisy in my environment and I failed to reduce the noise so far. numa01: mm-unstable: 146.88 +- 6.54 seconds time elapsed ( +- 4.45% ) mm-unstable++: 147.45 +- 13.39 seconds time elapsed ( +- 9.08% ) numa02: mm-unstable: 16.0300 +- 0.0624 seconds time elapsed ( +- 0.39% ) mm-unstable++: 16.1281 +- 0.0945 seconds time elapsed ( +- 0.59% ) It is worth noting that for shared writable mappings that require writenotify, we will only avoid write faults if the pte/pmd is dirty (inherited from the older mprotect logic). If we ever care about optimizing that further, we'd need a different mechanism to identify whether the FS still needs to get notified on the next write access. In any case, such an optimiztion will then not be autonuma-specific, but mprotect() permission upgrades would similarly benefit from it. Cc: Linus Torvalds Cc: Andrew Morton Cc: Mel Gorman Cc: Dave Chinner Cc: Nadav Amit Cc: Peter Xu Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Vlastimil Babka Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Mike Rapoport Cc: Anshuman Khandual v1 -> v2: * "mm/mprotect: factor out check whether manual PTE write upgrades are required" -> Added * "mm/autonuma: use can_change_(pte|pmd)_writable() to replace savedwrite" -> Simplify and don't opimize for failed migration -> Update patch description RFC -> v1: * "mm/mprotect: allow clean exclusive anon pages to be writable" -> Move comment change to patch #2 * "mm/mprotect: minor can_change_pte_writable() cleanups" -> Adjust comments * "mm/huge_memory: try avoiding write faults when changing PMD protection" -> Fix wrong check * "selftests/vm: anon_cow: add mprotect() optimiation tests" -> Add basic tests for the mprotect() optimization David Hildenbrand (6): mm/mprotect: minor can_change_pte_writable() cleanups mm/huge_memory: try avoiding write faults when changing PMD protection mm/mprotect: factor out check whether manual PTE write upgrades are required mm/autonuma: use can_change_(pte|pmd)_writable() to replace savedwrite mm: remove unused savedwrite infrastructure selftests/vm: anon_cow: add mprotect() optimization tests Nadav Amit (1): mm/mprotect: allow clean exclusive anon pages to be writable arch/powerpc/include/asm/book3s/64/pgtable.h | 80 +------------------- arch/powerpc/kvm/book3s_hv_rm_mmu.c | 2 +- include/linux/mm.h | 18 ++++- include/linux/pgtable.h | 24 ------ mm/debug_vm_pgtable.c | 32 -------- mm/huge_memory.c | 64 ++++++++++++---- mm/ksm.c | 9 +-- mm/memory.c | 16 +++- mm/mprotect.c | 50 ++++++------ tools/testing/selftests/vm/anon_cow.c | 49 +++++++++++- 10 files changed, 158 insertions(+), 186 deletions(-)