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 22715368952 for ; Thu, 26 Feb 2026 17:18:46 +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=1772126327; cv=none; b=lFxs+1b990v1rvHQDaDXU916Al/TtUm1DStl4CQ2biZvf5KHnc6DyyasUM/jQJa21KozzBsUO3eFZPNlZklX0qzuaD9wFksnmXDcYUMXKDPzEBY+/qTRB69LvNOWglYCF3jNIb+GAwjqWlyzg9jszpTIYmyy4b8EcFfFN7Vlf3U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772126327; c=relaxed/simple; bh=wCJnk1YaquKDJzRFpuEprsWkuiU+Hog6qx5jnO/MpfU=; h=Date:To:From:Subject:Message-Id; b=MWQGtc1V6IUOZ93nP0LOVAixYxJOI3BWOZfSHxuKjYpXSJ2xU7JCh4V5Ejc2AtGj6HsL38+pGI+qTmj/d5QVKDD9muvfTP1gHR0OvqBjqs1FPaXBbF90HBmCinwT9zV6k35tP77at0TO/W1WZYY/N806dt8CrZZtDZuMpepQDss= 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=AesKyMjW; 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="AesKyMjW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 998D2C116C6; Thu, 26 Feb 2026 17:18:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1772126326; bh=wCJnk1YaquKDJzRFpuEprsWkuiU+Hog6qx5jnO/MpfU=; h=Date:To:From:Subject:From; b=AesKyMjWHtLHJfbm1BWayvwl5K9PTYp8ol9IQQxyhpComS0XBqs7uqEHzRqtMMUVk 61HsiZtcFkckJVSmWCM1BSD+HLqVZGkPfC6eJgOvFRw5tvDeS2Kz8AsAx4bWAU9a6R Ldn+RyeGgB9qGNPPdoLg1nDueqoFbqaFfmPexbtA= Date: Thu, 26 Feb 2026 09:18:45 -0800 To: mm-commits@vger.kernel.org,ziy@nvidia.com,xuanzhuo@linux.alibaba.com,wei.liu@kernel.org,vbabka@suse.cz,surenb@google.com,mst@redhat.com,mhocko@suse.com,longli@microsoft.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-allow-zero-page_reporting_order.patch added to mm-new branch Message-Id: <20260226171846.998D2C116C6@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: allow zero page_reporting_order has been added to the -mm mm-new branch. Its filename is mm-page_reporting-allow-zero-page_reporting_order.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-allow-zero-page_reporting_order.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: allow zero page_reporting_order Date: Wed, 25 Feb 2026 23:01:23 -0800 Patch series "Allow order zero pages in page reporting". 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 patchset 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 3): Some drivers might require page sized chunks to be reported. This patch allows registering a driver with order as zero. Example use case: virtio-balloon driver running on a guest with very small memory. After some time has passed, the guest might not be able to find a chunk of 8KB. Link: https://lkml.kernel.org/r/20260226070125.3732265-1-yuvraj.sakshith@oss.qualcomm.com Link: https://lkml.kernel.org/r/20260226070125.3732265-2-yuvraj.sakshith@oss.qualcomm.com Signed-off-by: Yuvraj Sakshith Cc: Brendan Jackman Cc: David Hildenbrand Cc: Dexuan Cui Cc: Eugenio Pérez Cc: Haiyang Zhang Cc: Jason Wang Cc: Johannes Weiner Cc: K. Y. Srinivasan Cc: Long Li Cc: "Michael S. Tsirkin" Cc: Michal Hocko Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Wei Liu Cc: Xuan Zhuo Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/page_reporting.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/page_reporting.c~mm-page_reporting-allow-zero-page_reporting_order +++ a/mm/page_reporting.c @@ -370,7 +370,7 @@ int page_reporting_register(struct page_ */ if (page_reporting_order == -1) { - if (prdev->order > 0 && prdev->order <= MAX_PAGE_ORDER) + if (prdev->order >= 0 && 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-allow-zero-page_reporting_order.patch hv_balloon-change-default-page-reporting-order.patch virtio_balloon-set-pr_devorder-to-new-default.patch