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 4A5FAC7618E for ; Mon, 24 Apr 2023 22:34:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232791AbjDXWen (ORCPT ); Mon, 24 Apr 2023 18:34:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51260 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232987AbjDXWea (ORCPT ); Mon, 24 Apr 2023 18:34:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 980CF8A4E for ; Mon, 24 Apr 2023 15:34:25 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1DD32629C8 for ; Mon, 24 Apr 2023 22:34:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6A452C433D2; Mon, 24 Apr 2023 22:34:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1682375664; bh=y2lAl+zmBAIflDwar4RlOlc13Fz09eB8aDeSu/ZTecU=; h=Date:To:From:Subject:From; b=yb1xh0keXZmFs1qQdvv9Zjwg5lrsnzblbdQm8VotGQj9T4oKqumipaPcyOxV3ejZf QviqEt5e2DR4PQr6PYL4WPvga/ykNFz8tAAxMMO5FAveLQdGcyTD3iuWA3ljg/bcuC C7A4d8Sso5Xpjgum3yevOGGKDutJcALIGK5vymSs= Date: Mon, 24 Apr 2023 15:34:23 -0700 To: mm-commits@vger.kernel.org, svens@linux.ibm.com, shuah@kernel.org, shr@devkernel.io, riel@surriel.com, mhocko@suse.com, imbrenda@linux.ibm.com, hca@linux.ibm.com, hannes@cmpxchg.org, gor@linux.ibm.com, frankja@linux.ibm.com, borntraeger@linux.ibm.com, david@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-ksm-unmerge-and-clear-vm_mergeable-when-setting-pr_set_memory_merge=0.patch added to mm-unstable branch Message-Id: <20230424223424.6A452C433D2@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/ksm: unmerge and clear VM_MERGEABLE when setting PR_SET_MEMORY_MERGE=0 has been added to the -mm mm-unstable branch. Its filename is mm-ksm-unmerge-and-clear-vm_mergeable-when-setting-pr_set_memory_merge=0.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-ksm-unmerge-and-clear-vm_mergeable-when-setting-pr_set_memory_merge=0.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: David Hildenbrand Subject: mm/ksm: unmerge and clear VM_MERGEABLE when setting PR_SET_MEMORY_MERGE=0 Date: Sat, 22 Apr 2023 22:54:18 +0200 Patch series "mm/ksm: improve PR_SET_MEMORY_MERGE=0 handling and cleanup disabling KSM", v2. (1) Make PR_SET_MEMORY_MERGE=0 unmerge pages like setting MADV_UNMERGEABLE does, (2) add a selftest for it and (3) factor out disabling of KSM from s390/gmap code. This patch (of 3): 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. Link: https://lkml.kernel.org/r/20230422205420.30372-1-david@redhat.com Link: https://lkml.kernel.org/r/20230422205420.30372-2-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Stefan Roesch Cc: Christian Borntraeger Cc: Claudio Imbrenda Cc: Heiko Carstens Cc: Janosch Frank Cc: Johannes Weiner Cc: Michal Hocko Cc: Rik van Riel Cc: Shuah Khan Cc: Sven Schnelle Cc: Vasily Gorbik Signed-off-by: Andrew Morton --- include/linux/ksm.h | 1 kernel/sys.c | 12 ++------ mm/ksm.c | 59 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 63 insertions(+), 9 deletions(-) --- a/include/linux/ksm.h~mm-ksm-unmerge-and-clear-vm_mergeable-when-setting-pr_set_memory_merge=0 +++ a/include/linux/ksm.h @@ -21,6 +21,7 @@ int ksm_madvise(struct vm_area_struct *v 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); --- a/kernel/sys.c~mm-ksm-unmerge-and-clear-vm_mergeable-when-setting-pr_set_memory_merge=0 +++ a/kernel/sys.c @@ -2695,16 +2695,10 @@ SYSCALL_DEFINE5(prctl, int, option, unsi if (mmap_write_lock_killable(me->mm)) return -EINTR; - if (arg2) { + 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; - } + else + error = ksm_disable_merge_any(me->mm); mmap_write_unlock(me->mm); break; case PR_GET_MEMORY_MERGE: --- a/mm/ksm.c~mm-ksm-unmerge-and-clear-vm_mergeable-when-setting-pr_set_memory_merge=0 +++ a/mm/ksm.c @@ -2520,6 +2520,22 @@ static void __ksm_add_vma(struct vm_area 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_struc __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 +2599,35 @@ int ksm_enable_merge_any(struct mm_struc return 0; } +/** + * ksm_disable_merge_any - Disable merging on all compatible VMA's of the mm, + * previously enabled via ksm_enable_merge_any(). + * + * Disabling merging implies unmerging any merged pages, like setting + * MADV_UNMERGEABLE would. If unmerging fails, the whole operation fails and + * merging on all compatible VMA's remains enabled. + * + * @mm: Pointer to mm + * + * Returns 0 on success, otherwise error code + */ +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) { _ Patches currently in -mm which might be from david@redhat.com are mm-ksm-unmerge-and-clear-vm_mergeable-when-setting-pr_set_memory_merge=0.patch selftests-ksm-ksm_functional_tests-add-prctl-unmerge-test.patch mm-ksm-move-disabling-ksm-from-s390-gmap-code-to-ksm-code.patch