From patchwork Fri Feb 10 21:50:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13136490 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 11187C6379F for ; Fri, 10 Feb 2023 21:50:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233764AbjBJVu6 (ORCPT ); Fri, 10 Feb 2023 16:50:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233772AbjBJVu5 (ORCPT ); Fri, 10 Feb 2023 16:50:57 -0500 Received: from 66-220-144-178.mail-mxout.facebook.com (66-220-144-178.mail-mxout.facebook.com [66.220.144.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF57A635A0 for ; Fri, 10 Feb 2023 13:50:55 -0800 (PST) Received: by dev0134.prn3.facebook.com (Postfix, from userid 425415) id 776656BFC2CF; Fri, 10 Feb 2023 13:50:33 -0800 (PST) From: Stefan Roesch To: kernel-team@fb.com Cc: shr@devkernel.io, linux-mm@kvack.org, riel@surriel.com, mhocko@suse.com, david@redhat.com, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, akpm@linux-foundation.org Subject: [RFC PATCH v2 05/19] mm: support disabling of ksm for a process Date: Fri, 10 Feb 2023 13:50:09 -0800 Message-Id: <20230210215023.2740545-6-shr@devkernel.io> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230210215023.2740545-1-shr@devkernel.io> References: <20230210215023.2740545-1-shr@devkernel.io> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org This adds the ability to disable ksm for a process if ksm has been enabled for the process. Signed-off-by: Stefan Roesch --- mm/ksm.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/mm/ksm.c b/mm/ksm.c index efd8d3804de3..23d6944f78ad 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2690,6 +2690,27 @@ int __ksm_enter(struct mm_struct *mm, int flag) return 0; } +static void unmerge_vmas(struct mm_struct *mm) +{ + struct vm_area_struct *vma; + struct vma_iterator vmi; + + vma_iter_init(&vmi, mm, 0); + + mmap_read_lock(mm); + for_each_vma(vmi, vma) { + if (vma->vm_flags & VM_MERGEABLE) { + unsigned long flags = vma->vm_flags; + + if (ksm_madvise(vma, vma->vm_start, vma->vm_end, MADV_UNMERGEABLE, &flags)) + continue; + + vm_flags_clear(vma, VM_MERGEABLE); + } + } + mmap_read_unlock(mm); +} + void __ksm_exit(struct mm_struct *mm, int flag) { struct ksm_mm_slot *mm_slot; @@ -2697,8 +2718,10 @@ void __ksm_exit(struct mm_struct *mm, int flag) int easy_to_free = 0; if (!(current->flags & PF_EXITING) && flag == MMF_VM_MERGE_ANY && - test_bit(MMF_VM_MERGE_ANY, &mm->flags)) + test_bit(MMF_VM_MERGE_ANY, &mm->flags)) { clear_bit(MMF_VM_MERGE_ANY, &mm->flags); + unmerge_vmas(mm); + } /* * This process is exiting: if it's straightforward (as is the