From patchwork Tue Apr 18 15:28:47 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13215816 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 84868C77B75 for ; Tue, 18 Apr 2023 15:29:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231273AbjDRP3s (ORCPT ); Tue, 18 Apr 2023 11:29:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230423AbjDRP3r (ORCPT ); Tue, 18 Apr 2023 11:29:47 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3DC3BF9 for ; Tue, 18 Apr 2023 08:29:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681831741; 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: in-reply-to:in-reply-to:references:references; bh=lecfMikStSmpt+Q0WpS+JI6gz8j1FT0LsSw/UhC5P0k=; b=OkkSEgXsTuDlz5DR+jTr9WAMUi26Q6+Wsxg7WDxo20kYqf/GUuvFDkG/hvS84gQ1XS9vD9 OL6yMQqASWv4YnQ8ivGjqIZVdBQknYszlVY6qx/kqe0E12yNWXIYKUpYLmZQWNWXWhU1T6 mk1rF6E9/SCfFe9eQEeO7sT5esUDXAE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-637-58a_-S71MqC04QAAf1VC5A-1; Tue, 18 Apr 2023 11:28:58 -0400 X-MC-Unique: 58a_-S71MqC04QAAf1VC5A-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 78A5588905A; Tue, 18 Apr 2023 15:28:57 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.194.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5EE7914171B8; Tue, 18 Apr 2023 15:28:54 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-kselftest@vger.kernel.org, David Hildenbrand , Andrew Morton , Stefan Roesch , Rik van Riel , Johannes Weiner , Michal Hocko , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Sven Schnelle , Shuah Khan Subject: [PATCH v1 1/3] mm/ksm: unmerge and clear VM_MERGEABLE when setting PR_SET_MEMORY_MERGE=0 Date: Tue, 18 Apr 2023 17:28:47 +0200 Message-Id: <20230418152849.505124-2-david@redhat.com> In-Reply-To: <20230418152849.505124-1-david@redhat.com> References: <20230418051342.1919757-1-shr@devkernel.io> <20230418152849.505124-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Let's unmerge any KSM pages when setting PR_SET_MEMORY_MERGE=0, and clear the VM_MERGEABLE flag from all VMAs -- just like KSM would. Of course, only do that if we previously set PR_SET_MEMORY_MERGE=1. Signed-off-by: David Hildenbrand Acked-by: Stefan Roesch --- include/linux/ksm.h | 1 + kernel/sys.c | 7 +------ mm/ksm.c | 47 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 49 insertions(+), 6 deletions(-) diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 590934bdddcf..7108bc65dc2a 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -21,6 +21,7 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start, void ksm_add_vma(struct vm_area_struct *vma); int ksm_enable_merge_any(struct mm_struct *mm); +int ksm_disable_merge_any(struct mm_struct *mm); int __ksm_enter(struct mm_struct *mm); void __ksm_exit(struct mm_struct *mm); diff --git a/kernel/sys.c b/kernel/sys.c index 72cdb16e2636..3436376667d7 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2698,12 +2698,7 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, if (arg2) { error = ksm_enable_merge_any(me->mm); } else { - /* - * TODO: we might want disable KSM on all VMAs and - * trigger unsharing to completely disable KSM. - */ - clear_bit(MMF_VM_MERGE_ANY, &me->mm->flags); - error = 0; + error = ksm_disable_merge_any(me->mm); } mmap_write_unlock(me->mm); break; diff --git a/mm/ksm.c b/mm/ksm.c index a959e8925413..813f7fbc1832 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2520,6 +2520,22 @@ static void __ksm_add_vma(struct vm_area_struct *vma) vm_flags_set(vma, VM_MERGEABLE); } +static int __ksm_del_vma(struct vm_area_struct *vma) +{ + int err; + + if (!(vma->vm_flags & VM_MERGEABLE)) + return 0; + + if (vma->anon_vma) { + err = unmerge_ksm_pages(vma, vma->vm_start, vma->vm_end); + if (err) + return err; + } + + vm_flags_clear(vma, VM_MERGEABLE); + return 0; +} /** * ksm_add_vma - Mark vma as mergeable if compatible * @@ -2542,6 +2558,20 @@ static void ksm_add_vmas(struct mm_struct *mm) __ksm_add_vma(vma); } +static int ksm_del_vmas(struct mm_struct *mm) +{ + struct vm_area_struct *vma; + int err; + + VMA_ITERATOR(vmi, mm, 0); + for_each_vma(vmi, vma) { + err = __ksm_del_vma(vma); + if (err) + return err; + } + return 0; +} + /** * ksm_enable_merge_any - Add mm to mm ksm list and enable merging on all * compatible VMA's @@ -2569,6 +2599,23 @@ int ksm_enable_merge_any(struct mm_struct *mm) return 0; } +int ksm_disable_merge_any(struct mm_struct *mm) +{ + int err; + + if (!test_bit(MMF_VM_MERGE_ANY, &mm->flags)) + return 0; + + err = ksm_del_vmas(mm); + if (err) { + ksm_add_vmas(mm); + return err; + } + + clear_bit(MMF_VM_MERGE_ANY, &mm->flags); + return 0; +} + int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, unsigned long *vm_flags) { From patchwork Tue Apr 18 15:28:48 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13215817 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 2ACE5C6FD18 for ; Tue, 18 Apr 2023 15:30:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232267AbjDRPaf (ORCPT ); Tue, 18 Apr 2023 11:30:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231701AbjDRPad (ORCPT ); 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Tue, 18 Apr 2023 11:29:01 -0400 X-MC-Unique: tx5a0GuAONunj9TrLi1nxQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 048921C0A58F; Tue, 18 Apr 2023 15:29:00 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.194.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id B148314152F6; Tue, 18 Apr 2023 15:28:57 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-kselftest@vger.kernel.org, David Hildenbrand , Andrew Morton , Stefan Roesch , Rik van Riel , Johannes Weiner , Michal Hocko , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Sven Schnelle , Shuah Khan Subject: [PATCH v1 2/3] selftests/ksm: ksm_functional_tests: add prctl unmerge test Date: Tue, 18 Apr 2023 17:28:48 +0200 Message-Id: <20230418152849.505124-3-david@redhat.com> In-Reply-To: <20230418152849.505124-1-david@redhat.com> References: <20230418051342.1919757-1-shr@devkernel.io> <20230418152849.505124-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Let's test whether setting PR_SET_MEMORY_MERGE to 0 after setting it to 1 will unmerge pages, similar to how setting MADV_UNMERGEABLE after setting MADV_MERGEABLE would. Signed-off-by: David Hildenbrand Acked-by: Stefan Roesch --- .../selftests/mm/ksm_functional_tests.c | 46 ++++++++++++++++--- 1 file changed, 40 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c index 7bc9fc17c9f0..26853badae70 100644 --- a/tools/testing/selftests/mm/ksm_functional_tests.c +++ b/tools/testing/selftests/mm/ksm_functional_tests.c @@ -91,9 +91,10 @@ static int ksm_merge(void) return 0; } -static char *mmap_and_merge_range(char val, unsigned long size) +static char *mmap_and_merge_range(char val, unsigned long size, bool use_prctl) { char *map; + int ret; map = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0); @@ -110,7 +111,17 @@ static char *mmap_and_merge_range(char val, unsigned long size) /* Make sure each page contains the same values to merge them. */ memset(map, val, size); - if (madvise(map, size, MADV_MERGEABLE)) { + + if (use_prctl) { + ret = prctl(PR_SET_MEMORY_MERGE, 1, 0, 0, 0); + if (ret < 0 && errno == EINVAL) { + ksft_test_result_skip("PR_SET_MEMORY_MERGE not supported\n"); + goto unmap; + } else if (ret) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=1 failed\n"); + goto unmap; + } + } else if (madvise(map, size, MADV_MERGEABLE)) { ksft_test_result_fail("MADV_MERGEABLE failed\n"); goto unmap; } @@ -133,7 +144,7 @@ static void test_unmerge(void) ksft_print_msg("[RUN] %s\n", __func__); - map = mmap_and_merge_range(0xcf, size); + map = mmap_and_merge_range(0xcf, size, false); if (map == MAP_FAILED) return; @@ -155,7 +166,7 @@ static void test_unmerge_discarded(void) ksft_print_msg("[RUN] %s\n", __func__); - map = mmap_and_merge_range(0xcf, size); + map = mmap_and_merge_range(0xcf, size, false); if (map == MAP_FAILED) return; @@ -187,7 +198,7 @@ static void test_unmerge_uffd_wp(void) ksft_print_msg("[RUN] %s\n", __func__); - map = mmap_and_merge_range(0xcf, size); + map = mmap_and_merge_range(0xcf, size, false); if (map == MAP_FAILED) return; @@ -323,9 +334,31 @@ static void test_prctl_fork(void) ksft_test_result_pass("PR_SET_MEMORY_MERGE value is inherited\n"); } +static void test_prctl_unmerge(void) +{ + const unsigned int size = 2 * MiB; + char *map; + + ksft_print_msg("[RUN] %s\n", __func__); + + map = mmap_and_merge_range(0xcf, size, true); + if (map == MAP_FAILED) + return; + + if (prctl(PR_SET_MEMORY_MERGE, 0, 0, 0, 0)) { + ksft_test_result_fail("PR_SET_MEMORY_MERGE=0 failed\n"); + goto unmap; + } + + ksft_test_result(!range_maps_duplicates(map, size), + "Pages were unmerged\n"); +unmap: + munmap(map, size); +} + int main(int argc, char **argv) { - unsigned int tests = 4; + unsigned int tests = 5; int err; #ifdef __NR_userfaultfd @@ -355,6 +388,7 @@ int main(int argc, char **argv) test_prctl(); test_prctl_fork(); + test_prctl_unmerge(); err = ksft_get_fail_cnt(); if (err) From patchwork Tue Apr 18 15:28:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13215818 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 0C881C77B78 for ; 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Tue, 18 Apr 2023 11:29:03 -0400 X-MC-Unique: Je6gkD7QPgStNU4pQnR1yQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D3CDF8996F7; Tue, 18 Apr 2023 15:29:02 +0000 (UTC) Received: from t480s.redhat.com (unknown [10.39.194.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3F63F14171B8; Tue, 18 Apr 2023 15:29:00 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-kselftest@vger.kernel.org, David Hildenbrand , Andrew Morton , Stefan Roesch , Rik van Riel , Johannes Weiner , Michal Hocko , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Sven Schnelle , Shuah Khan Subject: [PATCH v1 3/3] mm/ksm: move disabling KSM from s390/gmap code to KSM code Date: Tue, 18 Apr 2023 17:28:49 +0200 Message-Id: <20230418152849.505124-4-david@redhat.com> In-Reply-To: <20230418152849.505124-1-david@redhat.com> References: <20230418051342.1919757-1-shr@devkernel.io> <20230418152849.505124-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Let's factor out actual disabling of KSM. The existing "mm->def_flags &= ~VM_MERGEABLE;" was essentially a NOP and can be dropped, because def_flags should never include VM_MERGEABLE. Note that we don't currently prevent re-enabling KSM. This should now be faster in case KSM was never enabled, because we only conditionally iterate all VMAs. Further, it certainly looks cleaner. Signed-off-by: David Hildenbrand Acked-by: Janosch Frank Acked-by: Stefan Roesch --- arch/s390/mm/gmap.c | 20 +------------------- include/linux/ksm.h | 6 ++++++ mm/ksm.c | 11 +++++++++++ 3 files changed, 18 insertions(+), 19 deletions(-) diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index 0949811761e6..dfe905c7bd8e 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -2585,30 +2585,12 @@ EXPORT_SYMBOL_GPL(s390_enable_sie); int gmap_mark_unmergeable(void) { - struct mm_struct *mm = current->mm; - struct vm_area_struct *vma; - unsigned long vm_flags; - int ret; - VMA_ITERATOR(vmi, mm, 0); - /* * Make sure to disable KSM (if enabled for the whole process or * individual VMAs). Note that nothing currently hinders user space * from re-enabling it. */ - clear_bit(MMF_VM_MERGE_ANY, &mm->flags); - - for_each_vma(vmi, vma) { - /* Copy vm_flags to avoid partial modifications in ksm_madvise */ - vm_flags = vma->vm_flags; - ret = ksm_madvise(vma, vma->vm_start, vma->vm_end, - MADV_UNMERGEABLE, &vm_flags); - if (ret) - return ret; - vm_flags_reset(vma, vm_flags); - } - mm->def_flags &= ~VM_MERGEABLE; - return 0; + return ksm_disable(current->mm); } EXPORT_SYMBOL_GPL(gmap_mark_unmergeable); diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 7108bc65dc2a..b3d8b7849e18 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -22,6 +22,7 @@ int ksm_madvise(struct vm_area_struct *vma, unsigned long start, void ksm_add_vma(struct vm_area_struct *vma); int ksm_enable_merge_any(struct mm_struct *mm); int ksm_disable_merge_any(struct mm_struct *mm); +int ksm_disable(struct mm_struct *mm); int __ksm_enter(struct mm_struct *mm); void __ksm_exit(struct mm_struct *mm); @@ -75,6 +76,11 @@ static inline void ksm_add_vma(struct vm_area_struct *vma) { } +static inline int ksm_disable(struct mm_struct *mm) +{ + return 0; +} + static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm) { return 0; diff --git a/mm/ksm.c b/mm/ksm.c index 813f7fbc1832..208311cbb019 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2616,6 +2616,17 @@ int ksm_disable_merge_any(struct mm_struct *mm) return 0; } +int ksm_disable(struct mm_struct *mm) +{ + mmap_assert_write_locked(mm); + + if (!test_bit(MMF_VM_MERGEABLE, &mm->flags)) + return 0; + if (test_bit(MMF_VM_MERGE_ANY, &mm->flags)) + return ksm_disable_merge_any(mm); + return ksm_del_vmas(mm); +} + int ksm_madvise(struct vm_area_struct *vma, unsigned long start, unsigned long end, int advice, unsigned long *vm_flags) {