This is a note to let you know that I've just added the patch titled
Drivers: hv: balloon: Ensure pressure reports are posted regularly
to the 3.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drivers-hv-balloon-ensure-pressure-reports-are-posted-regularly.patch
and it can be found in the queue-3.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ae339336dc950b9b05e7ccd3565dd3e8781c06d9 Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
Date: Wed, 23 Apr 2014 13:53:39 -0700
Subject: Drivers: hv: balloon: Ensure pressure reports are posted regularly
From: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
commit ae339336dc950b9b05e7ccd3565dd3e8781c06d9 upstream.
The current code posts periodic memory pressure status from a dedicated thread.
Under some conditions, especially when we are releasing a lot of memory into
the guest, we may not send timely pressure reports back to the host. Fix this
issue by reporting pressure in all contexts that can be active in this driver.
Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/hv/hv_balloon.c | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -19,6 +19,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
+#include <linux/jiffies.h>
#include <linux/mman.h>
#include <linux/delay.h>
#include <linux/init.h>
@@ -459,6 +460,11 @@ static bool do_hot_add;
*/
static uint pressure_report_delay = 45;
+/*
+ * The last time we posted a pressure report to host.
+ */
+static unsigned long last_post_time;
+
module_param(hot_add, bool, (S_IRUGO | S_IWUSR));
MODULE_PARM_DESC(hot_add, "If set attempt memory hot_add");
@@ -542,6 +548,7 @@ struct hv_dynmem_device {
static struct hv_dynmem_device dm_device;
+static void post_status(struct hv_dynmem_device *dm);
#ifdef CONFIG_MEMORY_HOTPLUG
static void hv_bring_pgs_online(unsigned long start_pfn, unsigned long size)
@@ -612,7 +619,7 @@ static void hv_mem_hot_add(unsigned long
* have not been "onlined" within the allowed time.
*/
wait_for_completion_timeout(&dm_device.ol_waitevent, 5*HZ);
-
+ post_status(&dm_device);
}
return;
@@ -951,11 +958,17 @@ static void post_status(struct hv_dynmem
{
struct dm_status status;
struct sysinfo val;
+ unsigned long now = jiffies;
+ unsigned long last_post = last_post_time;
if (pressure_report_delay > 0) {
--pressure_report_delay;
return;
}
+
+ if (!time_after(now, (last_post_time + HZ)))
+ return;
+
si_meminfo(&val);
memset(&status, 0, sizeof(struct dm_status));
status.hdr.type = DM_STATUS_REPORT;
@@ -983,6 +996,14 @@ static void post_status(struct hv_dynmem
if (status.hdr.trans_id != atomic_read(&trans_id))
return;
+ /*
+ * If the last post time that we sampled has changed,
+ * we have raced, don't post the status.
+ */
+ if (last_post != last_post_time)
+ return;
+
+ last_post_time = jiffies;
vmbus_sendpacket(dm->dev->channel, &status,
sizeof(struct dm_status),
(unsigned long)NULL,
@@ -1117,7 +1138,7 @@ static void balloon_up(struct work_struc
if (ret == -EAGAIN)
msleep(20);
-
+ post_status(&dm_device);
} while (ret == -EAGAIN);
if (ret) {
@@ -1144,8 +1165,10 @@ static void balloon_down(struct hv_dynme
struct dm_unballoon_response resp;
int i;
- for (i = 0; i < range_count; i++)
+ for (i = 0; i < range_count; i++) {
free_balloon_pages(dm, &range_array[i]);
+ post_status(&dm_device);
+ }
if (req->more_pages == 1)
return;
Patches currently in stable-queue which might be from kys@xxxxxxxxxxxxx are
queue-3.15/drivers-hv-balloon-ensure-pressure-reports-are-posted-regularly.patch
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