This patch enables the guest free page hinting support
to enable or disable based on the STATIC key which
could be set via sysctl.
Signed-off-by: Nitesh Narayan Lal <nitesh@xxxxxxxxxx>
---
include/linux/gfp.h | 2 ++
include/linux/page_hinting.h | 5 +++++
kernel/sysctl.c | 9 +++++++++
virt/kvm/page_hinting.c | 23 +++++++++++++++++++++++
4 files changed, 39 insertions(+)
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index e596527284ba..8389219a076a 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -461,6 +461,8 @@ static inline struct zonelist *node_zonelist(int nid, gfp_t flags)
#define HAVE_ARCH_FREE_PAGE
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
diff --git a/include/linux/page_hinting.h b/include/linux/page_hinting.h
index b54f7428f348..9bdcf63e1306 100644
--- a/include/linux/page_hinting.h
+++ b/include/linux/page_hinting.h
@@ -14,4 +14,9 @@ struct hypervisor_pages {
unsigned int order;
};
+extern int guest_page_hinting_flag;
+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);
void guest_free_page(struct page *page, int order);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ba4d9e85feb8..5d53629c9bfb 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1690,6 +1690,15 @@ static struct ctl_table vm_table[] = {
.extra1 = (void *)&mmap_rnd_compat_bits_min,
.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 818bd6b84e0c..4a34ea8db0c8 100644
--- a/virt/kvm/page_hinting.c
+++ b/virt/kvm/page_hinting.c
@@ -1,6 +1,7 @@
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/kernel.h>
+#include <linux/kvm_host.h>
/*
* struct kvm_free_pages - Tracks the pages which are freed by the guest.
@@ -31,6 +32,28 @@ struct page_hinting {
DEFINE_PER_CPU(struct page_hinting, hinting_obj);
+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;
+}
+
void guest_free_page(struct page *page, int order)
{
}
--
2.17.2
