[ACPI] Suspend to RAM fix

Free some RAM before entering S3 so that upon
resume we can be sure early allocations will succeed.

http://bugzilla.kernel.org/show_bug.cgi?id=3469

Signed-off-by: David Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index c7eb4a833db5..454434716f35 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -19,6 +19,9 @@
 
 #include "power.h"
 
+/*This is just an arbitrary number */
+#define FREE_PAGE_NUMBER (100)
+
 DECLARE_MUTEX(pm_sem);
 
 struct pm_ops * pm_ops = NULL;
@@ -49,6 +52,7 @@ void pm_set_ops(struct pm_ops * ops)
 static int suspend_prepare(suspend_state_t state)
 {
         int error = 0;
+        unsigned int free_pages;
 
         if (!pm_ops || !pm_ops->enter)
                 return -EPERM;
@@ -60,6 +64,16 @@ static int suspend_prepare(suspend_state_t state)
                 goto Thaw;
         }
 
+        if ((free_pages = nr_free_pages()) < FREE_PAGE_NUMBER) {
+                pr_debug("PM: free some memory\n");
+                shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
+                if (nr_free_pages() < FREE_PAGE_NUMBER) {
+                        error = -ENOMEM;
+                        printk(KERN_ERR "PM: No enough memory\n");
+                        goto Thaw;
+                }
+        }
+
         if (pm_ops->prepare) {
                 if ((error = pm_ops->prepare(state)))
                         goto Thaw;