From nobody Sat Feb 7 18:52:14 2026 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 01B4C1B142D; Mon, 19 Jan 2026 23:02:09 +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=1768863730; cv=none; b=iaRAsfhpjk2csggvuBK7RxqjSpAHDKnOVuxRSp3XzecQ3JWEnFidO2lQpN3UFamCXXn3iKVjY2rvLgI+usIah6cWYy6r0A8cC5oo+JOD8HPkoAX+ezY3bfyIZHACTEotxByzvv3VGoAnJynvd1ufF1R59MjRRzMXYoM+8wMl+TY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768863730; c=relaxed/simple; bh=9pFWzYgZbt+YY9kTe1GTcdn6HTneXxM/S/odovyu19w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fOn1F6sOGOPGfke3AdD6nUOQwsUJfRbhtjhOkMEAeCA087qOWetgjEPlFLJ4zNxPSv6hW68/jwzUWPwUVr0tY6vaCGxPSgRYbQDPEhvIyzTLiv/ZW9itXmFwEO2ApJk0eznIMW8NPAqfXvoXlxxOLGS3F5cB0zvTl7o8vjoVYlA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kLe0Khr6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kLe0Khr6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DCECC19424; Mon, 19 Jan 2026 23:02:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768863729; bh=9pFWzYgZbt+YY9kTe1GTcdn6HTneXxM/S/odovyu19w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kLe0Khr6DuCvasNoS6kxGtkTGY8Zw9brt5gCInhq8gLS+Ma4hsIx1369nWwQX1Tvf IB2XumFvNDI5jcl58bu1+Pu0ZrCudk7hz7m2H9Ax2cKzotO5pTZnVWOjCHvr53Owh9 wWCd3vv1ICESWBRIUrkH/QL8obmlOab1LlCb5uNL/xCEid0Q/hukDlzNIqcI0jUX7I MXYVPdAj/l45N6hoQMjhpukfeniE2KS3T4aRad/4Kfdv+ujJfbonv7OhpZdUpJlZdD v88zh6Y7ixYKz5JxWdDwhau0K/zyUQfHaZMYxvUzxiNBuApA2jLrvXlMoViRemVpHh F+IVwVmTXgxow== From: "David Hildenbrand (Red Hat)" To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, Broadcom internal kernel review list , linux-doc@vger.kernel.org, virtualization@lists.linux.dev, "David Hildenbrand (Red Hat)" , Andrew Morton , Oscar Salvador , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Arnd Bergmann , Greg Kroah-Hartman , Jerrin Shaji George , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Zi Yan Subject: [PATCH v3 04/24] mm/balloon_compaction: improve comments for WARN_ON_ONCE(!b_dev_info) Date: Tue, 20 Jan 2026 00:01:12 +0100 Message-ID: <20260119230133.3551867-5-david@kernel.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260119230133.3551867-1-david@kernel.org> References: <20260119230133.3551867-1-david@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Let's clarify a bit by extending the comments. Signed-off-by: David Hildenbrand (Red Hat) --- mm/balloon_compaction.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c index 03c5dbabb1565..85eea88cea083 100644 --- a/mm/balloon_compaction.c +++ b/mm/balloon_compaction.c @@ -222,7 +222,11 @@ static void balloon_page_putback(struct page *page) struct balloon_dev_info *b_dev_info =3D balloon_page_device(page); unsigned long flags; =20 - /* Isolated balloon pages cannot get deflated. */ + /* + * When we isolated the page, the page was still inflated in a balloon + * device. As isolated balloon pages cannot get deflated, we still have + * a balloon device here. + */ if (WARN_ON_ONCE(!b_dev_info)) return; =20 @@ -241,7 +245,11 @@ static int balloon_page_migrate(struct page *newpage, = struct page *page, VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); =20 - /* Isolated balloon pages cannot get deflated. */ + /* + * When we isolated the page, the page was still inflated in a balloon + * device. As isolated balloon pages cannot get deflated, we still have + * a balloon device here. + */ if (WARN_ON_ONCE(!balloon)) return -EAGAIN; =20 --=20 2.52.0