From: Nitesh Narayan Lal <nilal@xxxxxxxxxx>
This patch enables the guest page hinting support
to enable or disable based on the STATIC key which
could be set via sysctl.
Signed-off-by: Nitesh Narayan Lal <nilal@xxxxxxxxxx>
---
drivers/virtio/virtio_balloon.c | 16 +++++++++++-----
include/linux/gfp.h | 16 ++++++++++++++--
include/linux/page_hinting.h | 7 +++++++
kernel/sysctl.c | 9 +++++++++
virt/kvm/page_hinting.c | 29 +++++++++++++++++++++++++----
5 files changed, 66 insertions(+), 11 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 7aef032..e6457de 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -32,7 +32,6 @@
#include <linux/mm.h>
#include <linux/mount.h>
#include <linux/magic.h>
-#include <linux/page_hinting.h>
/*
* Balloon device works in 4K page units. So each page is pointed to by
@@ -124,6 +123,14 @@ static void hinting_ack(struct virtqueue *vq)
wake_up(&vb->acked);
}
+
+static void enable_hinting(struct virtio_balloon *vb)
+{
+ guest_page_hinting_flag = 1;
+ static_branch_enable(&guest_page_hinting_key);
+ request_hypercall = (void *)&virtballoon_page_hinting;
+ balloon_ptr = vb;
+}
#endif
static u32 page_to_balloon_pfn(struct page *page)
@@ -524,6 +531,7 @@ static int init_vqs(struct virtio_balloon *vb)
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
struct scatterlist sg;
unsigned int num_stats;
+
vb->stats_vq = vqs[2];
/*
@@ -685,10 +693,8 @@ static int virtballoon_probe(struct virtio_device *vdev)
virtio_device_ready(vdev);
#ifdef CONFIG_KVM_FREE_PAGE_HINTING
- if (virtio_has_feature(vb->vdev, VIRTIO_GUEST_PAGE_HINTING_VQ)) {
- request_hypercall = (void *)&virtballoon_page_hinting;
- balloon_ptr = vb;
- }
+ if (virtio_has_feature(vb->vdev, VIRTIO_GUEST_PAGE_HINTING_VQ))
+ enable_hinting(vb);
#endif
if (towards_target(vb))
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index e02369b..2212e08 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -7,6 +7,7 @@
#include <linux/stddef.h>
#include <linux/linkage.h>
#include <linux/topology.h>
+#include <linux/page_hinting.h>
struct vm_area_struct;
@@ -442,8 +443,19 @@ static inline struct zonelist *node_zonelist(int nid, gfp_t flags)
#ifdef CONFIG_KVM_FREE_PAGE_HINTING
#define HAVE_ARCH_ALLOC_PAGE
#define HAVE_ARCH_FREE_PAGE
-void arch_free_page(struct page *page, int order);
-void arch_alloc_page(struct page *page, int order);
+static inline void arch_alloc_page(struct page *page, int order)
+{
+ if (!static_branch_unlikely(&guest_page_hinting_key))
+ return;
+ guest_alloc_page(page, order);
+}
+
+static inline void arch_free_page(struct page *page, int order)
+{
+ if (!static_branch_unlikely(&guest_page_hinting_key))
+ return;
+ guest_free_page(page, order);
+}
#endif
#ifndef HAVE_ARCH_FREE_PAGE
diff --git a/include/linux/page_hinting.h b/include/linux/page_hinting.h
index 0bfb646..dd30644 100644
--- a/include/linux/page_hinting.h
+++ b/include/linux/page_hinting.h
@@ -14,3 +14,10 @@ struct hypervisor_pages {
extern struct hypervisor_pages hypervisor_pagelist[MAX_FGPT_ENTRIES];
extern void (*request_hypercall)(void *, int);
extern void *balloon_ptr;
+
+extern struct static_key_false guest_page_hinting_key;
+int guest_page_hinting_sysctl(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp, loff_t *ppos);
+extern int guest_page_hinting_flag;
+void guest_alloc_page(struct page *page, int order);
+void guest_free_page(struct page *page, int order);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 557d467..2717ceb 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1655,6 +1655,15 @@ static struct ctl_table vm_table[] = {
.extra2 = (void *)&mmap_rnd_compat_bits_max,
},
#endif
+#ifdef CONFIG_KVM_FREE_PAGE_HINTING
+ {
+ .procname = "guest-page-hinting",
+ .data = &guest_page_hinting_flag,
+ .maxlen = sizeof(guest_page_hinting_flag),
+ .mode = 0644,
+ .proc_handler = guest_page_hinting_sysctl,
+ },
+#endif
{ }
};
diff --git a/virt/kvm/page_hinting.c b/virt/kvm/page_hinting.c
index 22c892b..f66ad63 100644
--- a/virt/kvm/page_hinting.c
+++ b/virt/kvm/page_hinting.c
@@ -5,7 +5,6 @@
#include <linux/sort.h>
#include <linux/kernel.h>
#include <trace/events/kmem.h>
-#include <linux/page_hinting.h>
#define HYPERLIST_THRESHOLD 500
/*
@@ -30,6 +29,29 @@ void (*request_hypercall)(void *, int);
EXPORT_SYMBOL(request_hypercall);
void *balloon_ptr;
EXPORT_SYMBOL(balloon_ptr);
+struct static_key_false guest_page_hinting_key = STATIC_KEY_FALSE_INIT;
+EXPORT_SYMBOL(guest_page_hinting_key);
+static DEFINE_MUTEX(hinting_mutex);
+int guest_page_hinting_flag;
+EXPORT_SYMBOL(guest_page_hinting_flag);
+
+int guest_page_hinting_sysctl(struct ctl_table *table, int write,
+ void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret;
+
+ mutex_lock(&hinting_mutex);
+
+ ret = proc_dointvec(table, write, buffer, lenp, ppos);
+
+ if (guest_page_hinting_flag)
+ static_key_enable(&guest_page_hinting_key.key);
+ else
+ static_key_disable(&guest_page_hinting_key.key);
+ mutex_unlock(&hinting_mutex);
+ return ret;
+}
static void empty_hyperlist(void)
{
@@ -254,7 +276,7 @@ void arch_free_page_slowpath(void)
write_sequnlock(&guest_page_lock);
}
-void arch_alloc_page(struct page *page, int order)
+void guest_alloc_page(struct page *page, int order)
{
unsigned int seq;
@@ -270,12 +292,11 @@ void arch_alloc_page(struct page *page, int order)
trace_guest_alloc_page(page, order);
}
-void arch_free_page(struct page *page, int order)
+void guest_free_page(struct page *page, int order)
{
int *free_page_idx = &get_cpu_var(kvm_pt_idx);
struct kvm_free_pages *free_page_obj;
unsigned long flags;
-
/*
* use of global variables may trigger a race condition between irq and
* process context causing unwanted overwrites. This will be replaced
--
2.9.4
