From patchwork Fri Feb 10 21:50:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 13136492 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 7C279C64EC7 for ; Fri, 10 Feb 2023 21:50:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233772AbjBJVu7 (ORCPT ); Fri, 10 Feb 2023 16:50:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233790AbjBJVu5 (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 0DB786BABF for ; Fri, 10 Feb 2023 13:50:55 -0800 (PST) Received: by dev0134.prn3.facebook.com (Postfix, from userid 425415) id 72D2E6BFC2CB; 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 04/19] mm: invoke madvise for all vmas in scan_get_next_rmap_item Date: Fri, 10 Feb 2023 13:50:08 -0800 Message-Id: <20230210215023.2740545-5-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 If the new flag MMF_VM_MERGE_ANY has been set for a process, iterate over all the vmas and enable ksm if possible. For the vmas that can be ksm enabled this is only done once. Signed-off-by: Stefan Roesch --- mm/ksm.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/mm/ksm.c b/mm/ksm.c index 3597ae52fe7b..efd8d3804de3 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1063,6 +1063,7 @@ static int unmerge_and_remove_all_rmap_items(void) mm_slot_free(mm_slot_cache, mm_slot); clear_bit(MMF_VM_MERGEABLE, &mm->flags); + clear_bit(MMF_VM_MERGE_ANY, &mm->flags); mmdrop(mm); } else spin_unlock(&ksm_mmlist_lock); @@ -2329,6 +2330,17 @@ static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, return rmap_item; } +static bool vma_ksm_mergeable(struct vm_area_struct *vma) +{ + if (vma->vm_flags & VM_MERGEABLE) + return true; + + if (test_bit(MMF_VM_MERGE_ANY, &vma->vm_mm->flags)) + return true; + + return false; +} + static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) { struct mm_struct *mm; @@ -2405,8 +2417,20 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) goto no_vmas; for_each_vma(vmi, vma) { - if (!(vma->vm_flags & VM_MERGEABLE)) + if (!vma_ksm_mergeable(vma)) continue; + if (!(vma->vm_flags & VM_MERGEABLE)) { + unsigned long flags = vma->vm_flags; + + /* madvise failed, use next vma */ + if (ksm_madvise(vma, vma->vm_start, vma->vm_end, MADV_MERGEABLE, &flags)) + continue; + /* vma, not supported as being mergeable */ + if (!(flags & VM_MERGEABLE)) + continue; + + vm_flags_set(vma, VM_MERGEABLE); + } if (ksm_scan.address < vma->vm_start) ksm_scan.address = vma->vm_start; if (!vma->anon_vma) @@ -2491,6 +2515,7 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) mm_slot_free(mm_slot_cache, mm_slot); clear_bit(MMF_VM_MERGEABLE, &mm->flags); + clear_bit(MMF_VM_MERGE_ANY, &mm->flags); mmap_read_unlock(mm); mmdrop(mm); } else {