Hi Toshi,
2013/04/18 23:23, Toshi Kani wrote:
On Thu, 2013-04-18 at 17:36 +0900, Yasuaki Ishimatsu wrote:
When hot removing memory presented at boot time, following messages are shown:
:
diff --git a/kernel/resource.c b/kernel/resource.c
index 4aef886..637e8d2 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -21,6 +21,7 @@
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/pfn.h>
+#include <linux/mm.h>
#include <asm/io.h>
@@ -50,6 +51,16 @@ struct resource_constraint {
static DEFINE_RWLOCK(resource_lock);
+/*
+ * For memory hotplug, there is no way to free resource entries allocated
+ * by boot mem after the system is up. So for reusing the resource entry
+ * we need to remember the resource.
+ */
+struct resource bootmem_resource = {
+ .sibling = NULL,
+};
This should be a pointer of struct resource and declared as static, such
as:
static struct resource *bootmem_resource_free;
O.K. I'll update it.
+static DEFINE_SPINLOCK(bootmem_resource_lock);
+
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
@@ -151,6 +162,39 @@ __initcall(ioresources_init);
#endif /* CONFIG_PROC_FS */
+static void free_resource(struct resource *res)
+{
+ if (!res)
+ return;
+
+ if (PageSlab(virt_to_head_page(res))) {
+ spin_lock(&bootmem_resource_lock);
+ res->sibling = bootmem_resource.sibling;
+ bootmem_resource.sibling = res;
+ spin_unlock(&bootmem_resource_lock);
+ } else {
+ kfree(res);
+ }
+}
I second with Johannes.
I'll update it.
+static struct resource *get_resource(gfp_t flags)
+{
+ struct resource *res = NULL;
+
+ spin_lock(&bootmem_resource_lock);
+ if (bootmem_resource.sibling) {
+ res = bootmem_resource.sibling;
+ bootmem_resource.sibling = res->sibling;
+ memset(res, 0, sizeof(struct resource));
+ }
+ spin_unlock(&bootmem_resource_lock);
I prefer to keep memset() outside of the spin lock.
spin_lock(&bootmem_resource_lock);
if (..) {
:
spin_unlock(&bootmem_resource_lock);
memset(res, 0, sizeof(struct resource));
} else {
spin_unlock(&bootmem_resource_lock);
res = kzalloc(sizeof(struct resource), flags);
}
Hmm. It is a little ugly. How about it?
spin_lock(&bootmem_resource_lock);
if (bootmem_resource.sibling) {
res = bootmem_resource.sibling;
bootmem_resource.sibling = res->sibling;
}
spin_unlock(&bootmem_resource_lock);
if (res)
memset(res, 0, sizeof(struct resource));
else
res = kzalloc(sizeof(struct resource), flags);
Thanks,
Yasuaki Ishimatsu
Thanks,
-Toshi
+
+
+ return res;
+}
+
--
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