Send the v4 patch to mailing list.
changelog:
v1: add memory range to e820 table, and update the varibles max_pfn/max_low_pfn/high_memory
Peter[hpa]: memory hotplug make sense on 32-bit kernel for virtual environment.
Andi[ak]: No VM supports it currently, and 64bit is the important part for hotplug
Fengguang[wfg]: some review comments on function naming
v2: rename function update_pfn to update_end_of_memory_vars
KAMEZAWA[kame]: e820map is considerted to be stable, read-only after boot.
Fengguang[wfg]: rewrite function page_is_ram, make it friendly for hotplug.
v3: keep the old e820map, update the varible max_pfn, high_memory only
KAMEZAWA[kame]: suggest to use memory hotplug notifier. If it's allowed, it will
be cleaner.
Fengguang[wfg]: notifier is for _outsider_ subsystems. It smells a bit overkill to do
notifier _inside_ the hotplug code.
Fengguang[wfg]: suggest to update max_pfn/max_low_pfn/high_memory in arch/x86/mm/init_64.c:
arch_add_memory() now, for X86_64.
Later on we can add code to arch/x86/mm/init_32.c:arch_add_memory() for X86_32.
v4: update max_pfn/max_low_pfn/high_memory in arch/x86/mm/init_64.c:arch_add_memory() for x86_64,
and resent it to mailing list, since fengguang's page_is_ram patch was accepted,
Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel
The new added memory can not be access by interface /dev/mem, because we do not
update the variables high_memory, max_pfn and max_low_pfn.
Add a function update_end_of_memory_vars to update these variables for 64-bit
kernel.
CC: Andi Kleen <[email protected]>
CC: Li Haicheng <[email protected]>
Reviewed-by: Wu Fengguang <[email protected]>
Reviewed-by: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Shaohui Zheng <[email protected]>
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 5a4398a..acfc01a 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -49,6 +49,7 @@
#include <asm/numa.h>
#include <asm/cacheflush.h>
#include <asm/init.h>
+#include <linux/bootmem.h>
static unsigned long dma_reserve __initdata;
@@ -614,6 +615,21 @@ void __init paging_init(void)
* Memory hotplug specific functions
*/
#ifdef CONFIG_MEMORY_HOTPLUG
+/**
+ * After memory hotplug, the variable max_pfn, max_low_pfn and high_memory will
+ * be affected, it will be updated in this function.
+ */
+static inline void __meminit update_end_of_memory_vars(u64 start,
+ u64 size)
+{
+ unsigned long end_pfn = PFN_UP(start + size);
+
+ if (end_pfn > max_pfn) {
+ max_low_pfn = max_pfn = end_pfn;
+ high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
+ }
+}
+
/*
* Memory is added always to NORMAL zone. This means you will never get
* additional DMA/DMA32 memory.
@@ -633,6 +649,9 @@ int arch_add_memory(int nid, u64 start, u64 size)
ret = __add_pages(nid, zone, start_pfn, nr_pages);
WARN_ON_ONCE(ret);
--
Thanks & Regards,
Shaohuki
Shaohui,
Some style nitpicks..
> #ifdef CONFIG_MEMORY_HOTPLUG
> +/**
Should use /* here.
> + * After memory hotplug, the variable max_pfn, max_low_pfn and high_memory will
> + * be affected, it will be updated in this function.
> + */
> +static inline void __meminit update_end_of_memory_vars(u64 start,
The "inline" and "__meminit" are both redundant here.
> + max_low_pfn = max_pfn = end_pfn;
One assignment per line is preferred.
Thanks,
Fengguang
On Mon, Feb 01, 2010 at 12:41:24PM +0800, Wu Fengguang wrote:
> Shaohui,
>
> Some style nitpicks..
>
> > #ifdef CONFIG_MEMORY_HOTPLUG
> > +/**
>
> Should use /* here.
Agree.
>
> > + * After memory hotplug, the variable max_pfn, max_low_pfn and high_memory will
> > + * be affected, it will be updated in this function.
> > + */
> > +static inline void __meminit update_end_of_memory_vars(u64 start,
>
> The "inline" and "__meminit" are both redundant here.
will remove both.
>
> > + max_low_pfn = max_pfn = end_pfn;
>
> One assignment per line is preferred.
will change to 2 statements.
>
> Thanks,
> Fengguang
Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel
The new added memory can not be access by interface /dev/mem, because we do not
update the variables high_memory, max_pfn and max_low_pfn.
Add a function update_end_of_memory_vars to update these variables for 64-bit
kernel.
CC: Andi Kleen <[email protected]>
CC: Li Haicheng <[email protected]>
Reviewed-by: Wu Fengguang <[email protected]>
Reviewed-by: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Shaohui Zheng <[email protected]>
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 5198b9b..e1c9202 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -49,6 +49,7 @@
#include <asm/numa.h>
#include <asm/cacheflush.h>
#include <asm/init.h>
+#include <linux/bootmem.h>
static unsigned long dma_reserve __initdata;
@@ -616,6 +617,21 @@ void __init paging_init(void)
*/
#ifdef CONFIG_MEMORY_HOTPLUG
/*
+ * After memory hotplug, the variables max_pfn, max_low_pfn and high_memory will
+ * be affected, they will be updated in this function.
+ */
+static void update_end_of_memory_vars(u64 start, u64 size)
+{
+ unsigned long end_pfn = PFN_UP(start + size);
+
+ if (end_pfn > max_pfn) {
+ max_pfn = end_pfn;
+ max_low_pfn = end_pfn;
+ high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
+ }
+}
+
+/*
* Memory is added always to NORMAL zone. This means you will never get
* additional DMA/DMA32 memory.
*/
@@ -634,6 +650,9 @@ int arch_add_memory(int nid, u64 start, u64 size)
ret = __add_pages(nid, zone, start_pfn, nr_pages);
WARN_ON_ONCE(ret);
+ /* update max_pfn, max_low_pfn and high_memory */
+ update_end_of_memory_vars(start, size);
+
return ret;
}
EXPORT_SYMBOL_GPL(arch_add_memory);
--
Thanks & Regards,
Shaohui