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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D110AE9B365 for ; Mon, 2 Mar 2026 11:18:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1F69F6B0089; Mon, 2 Mar 2026 06:18:05 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A4C06B008A; Mon, 2 Mar 2026 06:18:05 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 05BFE6B008C; Mon, 2 Mar 2026 06:18:05 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id EA7D26B0089 for ; Mon, 2 Mar 2026 06:18:04 -0500 (EST) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id B3A4C1D24B for ; Mon, 2 Mar 2026 11:18:04 +0000 (UTC) X-FDA: 84500873688.07.623B548 Received: from mx0a-0031df01.pphosted.com (mx0a-0031df01.pphosted.com [205.220.168.131]) by imf30.hostedemail.com (Postfix) with ESMTP id 473BC80008 for ; Mon, 2 Mar 2026 11:18:02 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=qualcomm.com header.s=qcppdkim1 header.b=MHRcXxNn; dkim=pass header.d=oss.qualcomm.com header.s=google header.b=PuOyPwdn; spf=pass (imf30.hostedemail.com: domain of yuvraj.sakshith@oss.qualcomm.com designates 205.220.168.131 as permitted sender) smtp.mailfrom=yuvraj.sakshith@oss.qualcomm.com; dmarc=pass (policy=reject) header.from=qualcomm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1772450282; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=/iFgusvo1aPKir8ugITOqUipqQuZUj6mnHU5x4L5Mi4=; b=B0K/W2KjJc3NjdCBVjZASWO+BBG7FXhMiMHKR/MjIL5KVbM7Aq7IHlNnCt5KmMOqUSgM6j 9f/Pac1kTy2EZ2RttwxP++0PCYu1yHqCgf1BMUqnGw7zvRbItdHk2F/RiX6aOPVmm1+oFk 7dEQ+kZ9R/85oVWzZojR14Fb9KvfgfA= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=qualcomm.com header.s=qcppdkim1 header.b=MHRcXxNn; dkim=pass header.d=oss.qualcomm.com header.s=google header.b=PuOyPwdn; spf=pass (imf30.hostedemail.com: domain of yuvraj.sakshith@oss.qualcomm.com designates 205.220.168.131 as permitted sender) smtp.mailfrom=yuvraj.sakshith@oss.qualcomm.com; dmarc=pass (policy=reject) header.from=qualcomm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772450282; a=rsa-sha256; cv=none; b=WD/jfoJWMEs6iByFvqq+fU+8xHvcvJaXa+4LyP5q6Ek/aIi8E4C+P4WvS1MuUS4xLnttcR GAlgt0MH99G5jVcxtIuOmAYyoJ0anYUHmc/2SVA1zt2SSHLnGhLB/vxdJpQl6nQLf/Q4A2 2+Ul5i3krNUxix/MEdDg0pm5DylDQF0= Received: from pps.filterd (m0279864.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 62285Xeo662205 for ; Mon, 2 Mar 2026 11:18:01 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qualcomm.com; h= cc:content-transfer-encoding:date:from:message-id:mime-version :subject:to; s=qcppdkim1; bh=/iFgusvo1aPKir8ugITOqUipqQuZUj6mnHU 5x4L5Mi4=; b=MHRcXxNnbz5GIKwWQYVoaNUziQJIm1paESYHmUwIp8XM8ZrTtZQ kcWU5RPnyN+J/lK8HEO4xggNDAX87YEtX+uyGAs+gzkW4c0y660oCog5baGTwhwL /+nBuWpu2Sxgv1D99xyf0mQgaJiwF3slKBh2Qu9t/GvSWSUmHrout4pmtuUKjsjt /CKjluajet6WGWMAaPMLcnWZrcuEpKzXCek0kna0xqpSKnm5wH16juvw7rMIehIR 0KJ8oYt3tpIdqqB5yF3QVZNFVTrl2fS3fLFogoOoZz7dDz5baYaTEL8LIN2WvABr s0TfoEpl7QRHAEkWKwHTe+IMzQkw/PX/z4Q== Received: from mail-oi1-f197.google.com (mail-oi1-f197.google.com [209.85.167.197]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4cn6r2rrm6-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Mon, 02 Mar 2026 11:18:00 +0000 (GMT) Received: by mail-oi1-f197.google.com with SMTP id 5614622812f47-4648a1c3520so20928819b6e.0 for ; Mon, 02 Mar 2026 03:18:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1772450280; x=1773055080; darn=kvack.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=/iFgusvo1aPKir8ugITOqUipqQuZUj6mnHU5x4L5Mi4=; b=PuOyPwdnBKVZDMKutO5lRcA1AFYTzg8w13sm0PuVmbLe2MzaPMtbkrSzNLsmrgRkqp s4gyb7qfcCCmWxtOF4fIlXpviFToNS2mVMWu3jiKdDdeu2TFY9fZLFWkbxE84BhalElO v+5vggtJHQBuDjpz4SDMD8UxHNh73XnHOEYlR5i8efTEsoE7Tf+SjwCuC385HNpFpKmD WcFjq9NmqtJo6eta1mVicfCM5xSfH49P65XtaPRYhq3DFLbJANzciHCa7Nxvk8tZNP+r IhJWiIyF2qOHfEIJXadtGsLjMjWF7BWhBb7dwGrV4pwkMq163FgQ/dzUHMCII2REDezP +f8w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772450280; x=1773055080; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/iFgusvo1aPKir8ugITOqUipqQuZUj6mnHU5x4L5Mi4=; b=vWmYtVec/KfC+BYTHv6MarR7Cc5pL+CQEienBUv+DRp778J//4EAKabZsLddfAMb3K 3DQaPCZ98RuM3JkTus9J0xbLNWHJs2KjXJgd+SikydOeHKiFU7XS1q7JFwaiqHM0yQ0l YHdaqNTZCYghQQl+DAx+8gVKPQttfsZ+5iDFx5JZ1jfmpwHfd0tsiac4pUKRJMGqBqB2 uRIaX3wArolfAZU24uwbgWOCIIPnCxs2B2j8zw/ik63n8Mu3x+BF1Aoi/Y/VhVMm38Go xDArmVQ1wfRbN8scSnz7FQZ0rr2+JMJf8XIKzZSxrTdtIxX7yoPm7AQVk7tO8UDyUnit ouww== X-Gm-Message-State: AOJu0YwSsqXjh98mQ20r0aaFGxll0SpI85qDyeHG9izBNpC+uVhtZMJe Lvi0v4xmLljXPfERiDvELnZ4rPOWWuh1ZFlICXeDC0PTcKHUDM9mSKZ5WkhY7bNxAFthu4Q4JAp WwGxtE8Jbw2i9R/9cunpE+0r4Ax83Tb9SH7xqvGmo7HMnSF83REkbkg== X-Gm-Gg: ATEYQzw0S6x6vG5qywpzsUbnBEDjW/qgBMvnm0E1iK9NHriTxnQn5o38LmRpNV3+AxX puBiBLOBqe4727ytCTt+/LX+e30tT9xMmFSiy+JEP8TUnJNU5EgimFqEMhib+DddQetipF2XzJr bGQF75rt0hEzC4ezNFDfzEPrJIoiyBonn6C1aNPzy8benwZCW2tJDewV80dB0IruOTj3YcVZpZY UCMz0cqJitxyquECfruB4px+nCVNM0leFllS6kajbFM3uvR1ZsRC15QCe58tYyJMnu/NlElkjkZ 1AUme9o8vpFKbNItfMpN+VZ2u+qf8et3Uy5Sv5qNIL4sCdDyYJdSPD3Sih9XyNLjjucm8q9UcYj W7bpyv+O3w5oG8hh00UrG0BWheV9ghKz+466HC9UUtYKrdxUSQAPMsugp/N9LitYLccfRr1qUbP RZa8sl X-Received: by 2002:a05:6808:6c2:b0:462:d097:2467 with SMTP id 5614622812f47-464be972a89mr4750532b6e.7.1772450279939; Mon, 02 Mar 2026 03:17:59 -0800 (PST) X-Received: by 2002:a05:6808:6c2:b0:462:d097:2467 with SMTP id 5614622812f47-464be972a89mr4750514b6e.7.1772450279537; Mon, 02 Mar 2026 03:17:59 -0800 (PST) Received: from hu-ysakshit-lv.qualcomm.com (Global_NAT1.qualcomm.com. [129.46.96.20]) by smtp.gmail.com with ESMTPSA id 5614622812f47-464bb59b66fsm7354528b6e.10.2026.03.02.03.17.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Mar 2026 03:17:59 -0800 (PST) From: Yuvraj Sakshith To: akpm@linux-foundation.org, mst@redhat.com, david@kernel.org, jasowang@redhat.com, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com Cc: linux-mm@kvack.org, virtualization@lists.linux.dev, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, xuanzhuo@linux.alibaba.com, eperezma@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com Subject: [PATCH v2 0/4] Allow order zero pages in page reporting Date: Mon, 2 Mar 2026 03:17:53 -0800 Message-Id: <20260302111757.2191056-1-yuvraj.sakshith@oss.qualcomm.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: lU_4SQXnx0T66Tdx0YZrJmDAea_GLeJB X-Proofpoint-ORIG-GUID: lU_4SQXnx0T66Tdx0YZrJmDAea_GLeJB X-Authority-Analysis: v=2.4 cv=Hpp72kTS c=1 sm=1 tr=0 ts=69a571e8 cx=c_pps a=WJcna6AvsNCxL/DJwPP1KA==:117 a=ouPCqIW2jiPt+lZRy3xVPw==:17 a=Yq5XynenixoA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=DJpcGTmdVt4CTyJn9g5Z:22 a=9ecvtSpfVrh-a2M179QA:9 a=_Y9Zt4tPzoBS9L09Snn2:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzAyMDA5MyBTYWx0ZWRfX2WMPwxPDhUle BH2K2M/JbEyIGfptGuYBgV8cdzb977ve7UIHaFuf+BSE7fENGyfs4zYi7PyEvnkGTt2T4wxTpRp iwfutneCBFzwMaGL6BOqUCqJdXMhjHi+JTTzxZ7OSvXymncUiVFJNsiOVbUxdpdrFyOaxQYi0H/ rsUKatMZRNNuxplAuP1wvTQ2jwh0v/eUJ781Ea28gRZavvYW76vOD0UKF29B16RYWCGxpuXqL28 88iDh5x7WnYWEZVTb5Uan87zttbFLQGnowBh6UurMY2TEiwqhyb9M3npWFG6BdwiEYsQRqaYfAU LjMwlag0BXUdw27DT5dIN4ULEIYo/c521Nn28gQg+t9qgwHjHPaxa4iCqUqHJcn8Lo9inUNgMgI C/p5NuG5PF4OB+vypTYFMr2YX5lcTdoI6fxA2RNpj4RIGpzizmYuxy4IhrWJC/46YIlIhrm5SuE tYRl8OKC2kWukvRxRGA== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-02_03,2026-02-27_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 suspectscore=0 impostorscore=0 phishscore=0 priorityscore=1501 adultscore=0 bulkscore=0 malwarescore=0 clxscore=1015 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2602130000 definitions=main-2603020093 X-Rspam-User: X-Rspamd-Queue-Id: 473BC80008 X-Rspamd-Server: rspam08 X-Stat-Signature: x8pq5yk3wnwuoxnxjdfwp9amruspzofb X-HE-Tag: 1772450282-714657 X-HE-Meta: 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 uiDGzYSY 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Today, page reporting sets page_reporting_order in two ways: (1) page_reporting.page_reporting_order cmdline parameter (2) Driver can pass order while registering itself. In both cases, order zero is ignored by free page reporting because it is used to set page_reporting_order to a default value, like MAX_PAGE_ORDER. In some cases we might want page_reporting_order to be zero. For instance, when virtio-balloon runs inside a guest with tiny memory (say, 16MB), it might not be able to find a order 1 page (or in the worst case order MAX_PAGE_ORDER page) after some uptime. Page reporting should be able to return order zero pages back for optimal memory relinquishment. This patch changes the default fallback value from '0' to '-1' in all possible clients of free page reporting (hv_balloon and virtio-balloon) together with allowing '0' as a valid order in page_reporting_register(). Changes in v1: - Introduce PAGE_REPORTING_DEFAULT_ORDER macro (initially set to 0). - Make use of new macro in drivers (hv_balloon and virtio-balloon) working with page reporting. - Change PAGE_REPORTING_DEFAULT_ORDER to -1 as zero is a valid page order that can be requested. Changes in v2: - Better naming. Replace PAGE_REPORTING_DEFAULT_ORDER with PAGE_REPORTING_ORDER_UNSPECIFIED. This takes care of the situation where page reporting order is not specified in the commandline. - Minor commit message changes. Yuvraj Sakshith (4): mm/page_reporting: add PAGE_REPORTING_ORDER_UNSPECIFIED virtio_balloon: set unspecified page reporting order hv_balloon: set unspecified page reporting order mm/page_reporting: change PAGE_REPORTING_ORDER_UNSPECIFIED to -1 drivers/hv/hv_balloon.c | 2 +- drivers/virtio/virtio_balloon.c | 2 ++ include/linux/page_reporting.h | 1 + mm/page_reporting.c | 7 ++++--- 4 files changed, 8 insertions(+), 4 deletions(-) -- 2.34.1