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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Nicholas Tsirakis <niko.tsirakis@gmail.com>,
        Juergen Gross <jgross@suse.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 18/74] xen/balloon: fix ballooned page accounting without hotplug enabled
Date:   Tue,  7 Jan 2020 21:54:43 +0100
Message-Id: <20200107205148.640690645@linuxfoundation.org>
In-Reply-To: <20200107205135.369001641@linuxfoundation.org>
References: <20200107205135.369001641@linuxfoundation.org>
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From: Juergen Gross <jgross@suse.com>

[ Upstream commit c673ec61ade89bf2f417960f986bc25671762efb ]

When CONFIG_XEN_BALLOON_MEMORY_HOTPLUG is not defined
reserve_additional_memory() will set balloon_stats.target_pages to a
wrong value in case there are still some ballooned pages allocated via
alloc_xenballooned_pages().

This will result in balloon_process() no longer be triggered when
ballooned pages are freed in batches.

Reported-by: Nicholas Tsirakis <niko.tsirakis@gmail.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/xen/balloon.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 71a6deeb4e71..3f9260af701f 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -401,7 +401,8 @@ static struct notifier_block xen_memory_nb = {
 #else
 static enum bp_state reserve_additional_memory(void)
 {
-	balloon_stats.target_pages = balloon_stats.current_pages;
+	balloon_stats.target_pages = balloon_stats.current_pages +
+				     balloon_stats.target_unpopulated;
 	return BP_ECANCELED;
 }
 #endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
-- 
2.20.1