From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F10092F5095 for ; Wed, 2 Jul 2025 17:39:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751477943; cv=none; b=n2eB5jQ621ru57JhLr0ifpNhl2Qm4RiGp3BI1FUUEOGA9eoOlVREuWssPJk/6+sJhMptRq1wRRjfzARGsk9JW9etZ56Cqtbsw8rUBrhp0NttQlHir39Qjw+6yvyCxubwomkKu/Ujbaa8aA0UgRW2bDaTb/QAO4vkzAmiRQ0/CFg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751477943; c=relaxed/simple; bh=PR5n+2aQcD9TCkCHsh6GGkhAHVo6Tzk+C893LlE59JU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ldIEckJzGYrKz6Cl65Umkxv5QT7qpnnb2S+8BHup43f0vKNe09kd9faVOvt95RI+xabeXxIamBEZcTGW5Ouizsye3p8JtafXgu4rt2EFYm1HjwydczGAt0QAUlnWnJ/aq/1NNhOf79hdTudRigkJ7MVXHRqpE1X5fkhhmWp2mOc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Rrh1pLch; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Rrh1pLch" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1751477940; 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=t5kc7QGkeiDNyd1vpvu2YlBzltMT97zD9Hu2apFeViM=; b=Rrh1pLchY2/QZ8tovuh20noI9lm2yGKgXz0n3uXo4SEFFMQjeSVnPbB6kCjKu2YRwc5MVR f7U5pn4e90YfBDGeIshf86601LLzvaMxjMrXHx10hSZsJCe7nv2F2taCMVwJjhpZMqyv4b kphaTgnQgyWx/LEEzntSosgpxEn+4n8= Received: from mail-ot1-f70.google.com (mail-ot1-f70.google.com [209.85.210.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-558-YkbrSJ_XObezkLbNJwRkCQ-1; Wed, 02 Jul 2025 13:38:59 -0400 X-MC-Unique: YkbrSJ_XObezkLbNJwRkCQ-1 X-Mimecast-MFC-AGG-ID: YkbrSJ_XObezkLbNJwRkCQ_1751477938 Received: by mail-ot1-f70.google.com with SMTP id 46e09a7af769-73838f64415so4870218a34.3 for ; Wed, 02 Jul 2025 10:38:58 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1751477938; x=1752082738; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=t5kc7QGkeiDNyd1vpvu2YlBzltMT97zD9Hu2apFeViM=; b=oOuelD4+eVXDE6xuoQRwBk3LrMoDDjgw7W717nwfJMJ7QCJC9gEvusJQiWy1OcRh0K CgVhXPYDPCqwGDZ7a+SF3tbH4HVNj7r1uVr7WNN0xlz8LqvVgiCk7cVthDPNCxjeK3dP Rr/akYkmE7+xaPXgmElYAzD3D9B553ZFtfbHr/yix3Jdgf1gbLh92bMJ3gii68Gi3l8g 9AGY8DghCw/v5UGON65/ydLq+LbQqYFL6LDMgRFPW1qfI5mBjzMHTc06/o1vTzpwtf1g yUMKH8USDmQyucxOIS9+JltxnpbENYl4PvQ+/eKkT/exKXovbS0TgIYO+CniZQDWZBgT PnDw== X-Forwarded-Encrypted: i=1; AJvYcCWcs+n9Q9VZbHYyEG/muSURce8LhJ8eVQAYUiJjchciqoDnykFPB500Vno+zAiksn65j7Ts/qLUvt+rc3U=@vger.kernel.org X-Gm-Message-State: AOJu0Yz2i6K4afCjaBHQUISAuJRru0BW6XOHtIVKYux/wP5G0GaFoMSZ 49Lz+cy+3a0APlbdsUCs7W/qiGRsfwbC6y3HmGn0M5QKopE01buV54/vzrC3M1fJIXB/qhwNkiM hu/GlgWO6900MXkGgdOVeeI5rFqwScM0LWs5MKgyKQIVAOTNOdtalrWVxGkvB+wDgdA== X-Gm-Gg: ASbGncvVCszMauNsA15T1HeTMDoYnX3NkGrPhz9UKSa0Hcq+6RYbdncaqjPHlDRC/gZ jt+tzPLdRR3SoFY4sWG/VPE6k3XnIx+zivVZHu24GW6QW6sgRcZZ/kUbUXX3V/MmJloMdkn36V+ Bb/vVZLXyQZ9iUKQWb2bO1HKFKi+2bVFr+74DpeEKYu2tVze+e1nJcxu1tWsbIyB+ZI7OsXw7Zy 364CFwDwaHvlYhPpaYXkaaOMSVfSb3XpZjgNgRdECVUcIs5j9vM5bCelDmrUzmBbhxMPkaAH6vf hRlYDyhRx+BZt/zLmjD0/YdA X-Received: by 2002:a05:6808:1a17:b0:40b:4436:46b6 with SMTP id 5614622812f47-40b8911280cmr2880856b6e.37.1751477938263; Wed, 02 Jul 2025 10:38:58 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHdmoKE0spR7/KmpsUBXOZZSNIqASQZlCpgekGVNMtn3ZdZbAeHx4Uw+Ze21QoFB0abDOfubQ== X-Received: by 2002:a05:6808:1a17:b0:40b:4436:46b6 with SMTP id 5614622812f47-40b8911280cmr2880834b6e.37.1751477937870; Wed, 02 Jul 2025 10:38:57 -0700 (PDT) Received: from [192.168.2.110] ([69.156.206.24]) by smtp.gmail.com with ESMTPSA id 5614622812f47-40b3241f829sm2629594b6e.35.2025.07.02.10.38.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Jul 2025 10:38:57 -0700 (PDT) Message-ID: <3c0eb35d-86e2-45ea-b933-32989c28963a@redhat.com> Date: Wed, 2 Jul 2025 13:38:45 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] proc: kpagecount: use snapshot_page() To: Shivank Garg , david@redhat.com, willy@infradead.org Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lcapitulino@gmail.com References: <5e94d287b6174098938ddd9959cf3c0619fb610a.1750961812.git.luizcap@redhat.com> <3ee3adfc-5efc-43dd-9c75-23564fade7b3@amd.com> Content-Language: en-US, en-CA From: Luiz Capitulino In-Reply-To: <3ee3adfc-5efc-43dd-9c75-23564fade7b3@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2025-07-02 02:25, Shivank Garg wrote: > > > On 6/26/2025 11:46 PM, Luiz Capitulino wrote: >> Currently, the call to folio_precise_page_mapcount() from kpage_read() >> can race with a folio split. When the race happens we trigger a >> VM_BUG_ON_FOLIO() in folio_entire_mapcount() (see splat below). >> >> This commit fixes this race by using snapshot_page() so that we >> retreive the folio mapcount using a folio snapshot. > > s/retreive/retrieve/ > checkpatch.pl would have flagged this. Thanks for pointing this out. I do run checkpatch.pl before sending patches, I don't know how I missed this. > > Rest looks good to me. > > Thanks, > Shivank >