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;
> +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.
> +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);
}
Thanks,
-Toshi
> +
> + if (!res)
> + res = kzalloc(sizeof(struct resource), flags);
> +
> + return res;
> +}
> +
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