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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6E75C433EF for ; Thu, 17 Mar 2022 12:32:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0F93B8D0001; Thu, 17 Mar 2022 08:32:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0A8966B0072; Thu, 17 Mar 2022 08:32:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EB1B68D0001; Thu, 17 Mar 2022 08:32:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0194.hostedemail.com [216.40.44.194]) by kanga.kvack.org (Postfix) with ESMTP id DA9916B0071 for ; Thu, 17 Mar 2022 08:32:53 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 8DAD31825FC6A for ; Thu, 17 Mar 2022 12:32:53 +0000 (UTC) X-FDA: 79253817426.23.8BBDF37 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf05.hostedemail.com (Postfix) with ESMTP id 08559100017 for ; Thu, 17 Mar 2022 12:32:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647520372; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RqZn3YEdFU/3QM8GNjB727vmGwyW7baEAHXNzBFmN58=; b=P+7EcgeDBk2HgeKO/dKNZ/V/oI3KFHDXgqi1NN++H78lt0VG28G6qjyI6Il0sJkQOOhNfI GuuwKGKwb88/7vX+ls7om1Zzmc3vPTiAvTHkNZr2fIktlGBwcXlSdeTe++gpt+9uA4wYIk DXeUssbJyBCVakB7eE/eMd5+CQB2mw8= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-283-y3sQKNzyMeKjduYHTzAQPg-1; Thu, 17 Mar 2022 08:32:51 -0400 X-MC-Unique: y3sQKNzyMeKjduYHTzAQPg-1 Received: by mail-wm1-f70.google.com with SMTP id i6-20020a05600c354600b0038be262d9d9so3067648wmq.8 for ; Thu, 17 Mar 2022 05:32:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=RqZn3YEdFU/3QM8GNjB727vmGwyW7baEAHXNzBFmN58=; b=ycrmk6jZH98BVa9bMC2FYCSAqjzM6iTkqVtQbqhXNKJSbgojIvOocXWqM8Mg0dTR9S 5E6GMeBP6HTT2jmkGYvvUXa+NHCQwXVdEMwVgGnC87XsCIydraiAA5FWg+PBJNhz4O/Q Py6MeIsu5BzodHwU5UGQdbC2CBHNC2lurET5w/WJ7heBarT+++839YswQZMHyPzkiXlQ 3ng5ECvosEgBKpgCo4xO+dP4Cyr3FGyavl7W555ZuBFVVCgWtUN2FhNZWhvz7mxwJKuw tpNoUg/DONVkJFg/K0qQTosraRaZPmgASRt3C7vFVjGCVtnQgXn0gZ6bRX6tJijfLsIj OLdQ== X-Gm-Message-State: AOAM531PKaL9Hbi6aSEvWZ8I+WOpImQPLMbF/7C0fstEfclLvHoWF+wb d1g8bTMRvqdpWeNp7gnsF3p8wvRe5Vh87E+VU7lU0MFgOgrpFabnH/OG4CMWBDrsWkotb9cOaVu gqw0+4cY4pZo= X-Received: by 2002:a05:600c:35ce:b0:389:ec57:1d7f with SMTP id r14-20020a05600c35ce00b00389ec571d7fmr11300164wmq.149.1647520370167; Thu, 17 Mar 2022 05:32:50 -0700 (PDT) X-Google-Smtp-Source: ABdhPJz3JJPrnhs22W6QOIN0f6W698/5NBzUwmz9dFnbq5r13BFbXwjnF9xBibZjPDlORrMQzpMBjg== X-Received: by 2002:a05:600c:35ce:b0:389:ec57:1d7f with SMTP id r14-20020a05600c35ce00b00389ec571d7fmr11300146wmq.149.1647520369813; Thu, 17 Mar 2022 05:32:49 -0700 (PDT) Received: from ?IPV6:2a09:80c0:192:0:20af:34be:985b:b6c8? ([2a09:80c0:192:0:20af:34be:985b:b6c8]) by smtp.gmail.com with ESMTPSA id v13-20020adfe28d000000b0020375f27a5asm4109290wri.4.2022.03.17.05.32.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 17 Mar 2022 05:32:49 -0700 (PDT) Message-ID: Date: Thu, 17 Mar 2022 13:32:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.6.2 Subject: Re: [PATCH v2] mm: add access/dirty bit on numa page fault To: Bibo Mao , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Anshuman Khandual References: <20220317065033.2635123-1-maobibo@loongson.cn> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20220317065033.2635123-1-maobibo@loongson.cn> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 08559100017 X-Stat-Signature: h5g9t7au6fzubhb5jyrx3pwmsq8pnih4 Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=P+7EcgeD; spf=none (imf05.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-HE-Tag: 1647520372-60274 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 17.03.22 07:50, Bibo Mao wrote: > On platforms like x86/arm which supports hw page walking, access > and dirty bit is set by hw, however on some platforms without > such hw functions, access and dirty bit is set by software in > next trap. > > During numa page fault, dirty bit can be added for old pte if > fail to migrate on write fault. And if it succeeds to migrate, > access bit can be added for migrated new pte, also dirty bit > can be added for write fault. > > Signed-off-by: Bibo Mao > --- > mm/memory.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/mm/memory.c b/mm/memory.c > index c125c4969913..65813bec9c06 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4404,6 +4404,22 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) > if (migrate_misplaced_page(page, vma, target_nid)) { > page_nid = target_nid; > flags |= TNF_MIGRATED; > + > + /* > + * update pte entry with access bit, and dirty bit for > + * write fault > + */ > + spin_lock(vmf->ptl); Ehm, are you sure? We did a pte_unmap_unlock(), so you most certainly need a vmf->pte = pte_offset_map(vmf->pmd, vmf->address); Also, don't we need pte_same() checks before we do anything after dropping the PT lock? > + pte = *vmf->pte; > + pte = pte_mkyoung(pte); > + if (was_writable) { > + pte = pte_mkwrite(pte); > + if (vmf->flags & FAULT_FLAG_WRITE) > + pte = pte_mkdirty(pte); > + } > + set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); > + update_mmu_cache(vma, vmf->address, vmf->pte); > + pte_unmap_unlock(vmf->pte, vmf->ptl); > } else { > flags |= TNF_MIGRATE_FAIL; > vmf->pte = pte_offset_map(vmf->pmd, vmf->address); > @@ -4427,8 +4443,11 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) > old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); > pte = pte_modify(old_pte, vma->vm_page_prot); > pte = pte_mkyoung(pte); > - if (was_writable) > + if (was_writable) { > pte = pte_mkwrite(pte); > + if (vmf->flags & FAULT_FLAG_WRITE) > + pte = pte_mkdirty(pte); > + } > ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); > update_mmu_cache(vma, vmf->address, vmf->pte); > pte_unmap_unlock(vmf->pte, vmf->ptl); -- Thanks, David / dhildenb