[PATCH 5.15 08/73] Drivers: hv: balloon: Support status report for larger page sizes

Greg Kroah-Hartman
2022-09-02T12:45:28Z

From: Boqun Feng <boqun.feng@gmail.com>

commit b3d6dd09ff00fdcf4f7c0cb54700ffd5dd343502 upstream.

DM_STATUS_REPORT expects the numbers of pages in the unit of 4k pages
(HV_HYP_PAGE) instead of guest pages, so to make it work when guest page
sizes are larger than 4k, convert the numbers of guest pages into the
numbers of HV_HYP_PAGEs.

Note that the numbers of guest pages are still used for tracing because
tracing is internal to the guest kernel.

Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220325023212.1570049-2-boqun.feng@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hv/hv_balloon.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -17,6 +17,7 @@
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/completion.h>
+#include <linux/count_zeros.h>
#include <linux/memory_hotplug.h>
#include <linux/memory.h>
#include <linux/notifier.h>
@@ -1130,6 +1131,7 @@ static void post_status(struct hv_dynmem
struct dm_status status;
unsigned long now = jiffies;
unsigned long last_post = last_post_time;
+ unsigned long num_pages_avail, num_pages_committed;

if (pressure_report_delay > 0) {
--pressure_report_delay;
@@ -1154,16 +1156,21 @@ static void post_status(struct hv_dynmem
* num_pages_onlined) as committed to the host, otherwise it can try
* asking us to balloon them out.
*/
- status.num_avail = si_mem_available();
- status.num_committed = vm_memory_committed() +
+ num_pages_avail = si_mem_available();
+ num_pages_committed = vm_memory_committed() +
dm->num_pages_ballooned +
(dm->num_pages_added > dm->num_pages_onlined ?
dm->num_pages_added - dm->num_pages_onlined : 0) +
compute_balloon_floor();

- trace_balloon_status(status.num_avail, status.num_committed,
+ trace_balloon_status(num_pages_avail, num_pages_committed,
vm_memory_committed(), dm->num_pages_ballooned,
dm->num_pages_added, dm->num_pages_onlined);
+
+ /* Convert numbers of pages into numbers of HV_HYP_PAGEs. */
+ status.num_avail = num_pages_avail * NR_HV_HYP_PAGES_IN_PAGE;
+ status.num_committed = num_pages_committed * NR_HV_HYP_PAGES_IN_PAGE;
+
/*
* If our transaction ID is no longer current, just don't
* send the status. This can happen if we were interrupted