Mailing List Archive: [PATCH] memory hotplug: fix early allocation handling

[PATCH] memory hotplug: fix early allocation handling

May 20, 2008, 3:51 AM

Post #1 of 3 (727 views)

From: Heiko Carstens <heiko.carstens@de.ibm.com>

Trying to add memory via add_memory() from within an initcall function
results in

bootmem alloc of 163840 bytes failed!
Kernel panic - not syncing: Out of memory

This is caused by zone_wait_table_init() which uses system_state to
decide if it should use the bootmem allocator or not.
When initcalls are handled the system_state is still SYSTEM_BOOTING
but the bootmem allocator doesn't work anymore. So the allocation
will fail.

To fix this use slab_is_available() instead as indicator like we do
it everywhere else.

Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
---
mm/page_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c
@@ -2804,7 +2804,7 @@ int zone_wait_table_init(struct zone *zo
alloc_size = zone->wait_table_hash_nr_entries
* sizeof(wait_queue_head_t);

- if (system_state == SYSTEM_BOOTING) {
+ if (!slab_is_available()) {
zone->wait_table = (wait_queue_head_t *)
alloc_bootmem_node(pgdat, alloc_size);
} else {
--
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Re: [PATCH] memory hotplug: fix early allocation handling [ In reply to ]

apw at shadowen

May 20, 2008, 7:48 AM

Post #2 of 3 (711 views)

Permalink

On Tue, May 20, 2008 at 12:51:45PM +0200, Heiko Carstens wrote:
> From: Heiko Carstens <heiko.carstens@de.ibm.com>
>
> Trying to add memory via add_memory() from within an initcall function
> results in
>
> bootmem alloc of 163840 bytes failed!
> Kernel panic - not syncing: Out of memory
>
> This is caused by zone_wait_table_init() which uses system_state to
> decide if it should use the bootmem allocator or not.
> When initcalls are handled the system_state is still SYSTEM_BOOTING
> but the bootmem allocator doesn't work anymore. So the allocation
> will fail.
>
> To fix this use slab_is_available() instead as indicator like we do
> it everywhere else.
>
> Cc: Andy Whitcroft <apw@shadowen.org>
> Cc: Dave Hansen <haveblue@us.ibm.com>
> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
> ---
> mm/page_alloc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-2.6/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.orig/mm/page_alloc.c
> +++ linux-2.6/mm/page_alloc.c
> @@ -2804,7 +2804,7 @@ int zone_wait_table_init(struct zone *zo
> alloc_size = zone->wait_table_hash_nr_entries
> * sizeof(wait_queue_head_t);
>
> - if (system_state == SYSTEM_BOOTING) {
> + if (!slab_is_available()) {
> zone->wait_table = (wait_queue_head_t *)
> alloc_bootmem_node(pgdat, alloc_size);
> } else {

It would be nice to be able to check that bootmem is enabled separatly
from whether slab is available, as I am sure there is a time where
neither is available during the change over. But the change looks
reasonable as we cannot use vmalloc until slab is working.

Reviewed-by: Andy Whitcroft <apw@shadowen.org>

-apw
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Re: [PATCH] memory hotplug: fix early allocation handling [ In reply to ]

y-goto at jp

May 21, 2008, 12:29 AM

Post #3 of 3 (705 views)

Permalink

Looks good to me.

Thanks.

Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com>

> From: Heiko Carstens <heiko.carstens@de.ibm.com>
>
> Trying to add memory via add_memory() from within an initcall function
> results in
>
> bootmem alloc of 163840 bytes failed!
> Kernel panic - not syncing: Out of memory
>
> This is caused by zone_wait_table_init() which uses system_state to
> decide if it should use the bootmem allocator or not.
> When initcalls are handled the system_state is still SYSTEM_BOOTING
> but the bootmem allocator doesn't work anymore. So the allocation
> will fail.
>
> To fix this use slab_is_available() instead as indicator like we do
> it everywhere else.
>
> Cc: Andy Whitcroft <apw@shadowen.org>
> Cc: Dave Hansen <haveblue@us.ibm.com>
> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
> ---
> mm/page_alloc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-2.6/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.orig/mm/page_alloc.c
> +++ linux-2.6/mm/page_alloc.c
> @@ -2804,7 +2804,7 @@ int zone_wait_table_init(struct zone *zo
> alloc_size = zone->wait_table_hash_nr_entries
> * sizeof(wait_queue_head_t);
>
> - if (system_state == SYSTEM_BOOTING) {
> + if (!slab_is_available()) {
> zone->wait_table = (wait_queue_head_t *)
> alloc_bootmem_node(pgdat, alloc_size);
> } else {

--
Yasunori Goto

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