From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5371B2EE611 for ; Tue, 3 Mar 2026 22:34:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772577281; cv=none; b=C/DS8kMuoaAMaL6xeALAjtYgHDgfyvx/p0//MVxXf58924pjztkeiFKV+Q6nR40n/GFTJdGt01+3mnJtrvnotcxz+8nmsa+8LmWhsYMsjGPeHsqhMrtZRB4nkQQUiZuBHY13HhGOjgE0NWZ0MPyVcGSF5hw6lhP2MIdz+grc9zo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772577281; c=relaxed/simple; bh=EcuDgR1s1PB5bcheC9LQ+XHtdTDqhlyuX3/fB7KWsqY=; h=Date:To:From:Subject:Message-Id; b=EFhaRUqsX4z9qo3SJtVLUIxXlgylhSbat7st+LK0DjF1TnmjyDZwgJ7spOhpWxp96P7ncG+QZxB2yYXpShX4O+lc356wJAapnOIn4lnn1QuDk/9UMJ8H4eM9Fp0H4zhCzsGd8geSTT0lLV71Bf+w+9QOb1SZv/WIYOUaxWbGb2c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=nM4cAeNE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="nM4cAeNE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BD9F0C116C6; Tue, 3 Mar 2026 22:34:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1772577280; bh=EcuDgR1s1PB5bcheC9LQ+XHtdTDqhlyuX3/fB7KWsqY=; h=Date:To:From:Subject:From; b=nM4cAeNESUOYTW7dQ6zfdYtEmmzwjAxaccwHe0qYTC8hJMcyxTgNwWtgvCGKYi/DH M9NAMY+KrSzINvnTa/Jm9NE2QqxGmTiyBR0P/XAgNvNFe9b60mr7cm77Z1tJlDdRs0 Tfxvdth0iAT3nH5noRUu8EVYX9urosbg1Le3mktc= Date: Tue, 03 Mar 2026 14:34:40 -0800 To: mm-commits@vger.kernel.org,ziy@nvidia.com,xuanzhuo@linux.alibaba.com,wei.liu@kernel.org,vbabka@suse.cz,surenb@google.com,rppt@kernel.org,mst@redhat.com,mhocko@suse.com,mhklinux@outlook.com,lorenzo.stoakes@oracle.com,longli@microsoft.com,liam.howlett@oracle.com,kys@microsoft.com,jasowang@redhat.com,jackmanb@google.com,hannes@cmpxchg.org,haiyangz@microsoft.com,eperezma@redhat.com,decui@microsoft.com,david@kernel.org,yuvraj.sakshith@oss.qualcomm.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-page_reporting-add-page_reporting_order_unspecified.patch added to mm-new branch Message-Id: <20260303223440.BD9F0C116C6@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/page_reporting: add PAGE_REPORTING_ORDER_UNSPECIFIED has been added to the -mm mm-new branch. Its filename is mm-page_reporting-add-page_reporting_order_unspecified.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_reporting-add-page_reporting_order_unspecified.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Yuvraj Sakshith Subject: mm/page_reporting: add PAGE_REPORTING_ORDER_UNSPECIFIED Date: Tue, 3 Mar 2026 03:30:28 -0800 Patch series "Allow order zero pages in page reporting", v4. 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(). This patch (of 5): Drivers can pass order of pages to be reported while registering itself. Today, this is a magic number, 0. Label this with PAGE_REPORTING_ORDER_UNSPECIFIED and check for it when the driver is being registered. This macro will be used in relevant drivers next. Link: https://lkml.kernel.org/r/20260303113032.3008371-1-yuvraj.sakshith@oss.qualcomm.com Link: https://lkml.kernel.org/r/20260303113032.3008371-2-yuvraj.sakshith@oss.qualcomm.com Signed-off-by: Yuvraj Sakshith Acked-by: David Hildenbrand (Arm) Reviewed-by: Michael Kelley Acked-by: Michael S. Tsirkin Cc: Brendan Jackman Cc: Dexuan Cui Cc: Eugenio Pérez Cc: Haiyang Zhang Cc: Jason Wang Cc: Johannes Weiner Cc: K. Y. Srinivasan Cc: Liam Howlett Cc: Long Li Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Wei Liu Cc: Xuan Zhuo Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/page_reporting.h | 1 + mm/page_reporting.c | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) --- a/include/linux/page_reporting.h~mm-page_reporting-add-page_reporting_order_unspecified +++ a/include/linux/page_reporting.h @@ -7,6 +7,7 @@ /* This value should always be a power of 2, see page_reporting_cycle() */ #define PAGE_REPORTING_CAPACITY 32 +#define PAGE_REPORTING_ORDER_UNSPECIFIED 0 struct page_reporting_dev_info { /* function that alters pages to make them "reported" */ --- a/mm/page_reporting.c~mm-page_reporting-add-page_reporting_order_unspecified +++ a/mm/page_reporting.c @@ -371,7 +371,8 @@ int page_reporting_register(struct page_ */ if (page_reporting_order == -1) { - if (prdev->order > 0 && prdev->order <= MAX_PAGE_ORDER) + if (prdev->order != PAGE_REPORTING_ORDER_UNSPECIFIED && + prdev->order <= MAX_PAGE_ORDER) page_reporting_order = prdev->order; else page_reporting_order = pageblock_order; _ Patches currently in -mm which might be from yuvraj.sakshith@oss.qualcomm.com are mm-page_reporting-add-page_reporting_order_unspecified.patch virtio_balloon-set-unspecified-page-reporting-order.patch hv_balloon-set-unspecified-page-reporting-order.patch mm-page_reporting-change-page_reporting_order_unspecified-to-1.patch mm-page_reporting-change-page_reporting_order-to-page_reporting_order_unspecified.patch