Re: [PATCH][BUGFIX] memcg: fix page_cgroup allocation

From: Andrew Morton
Date: Tue Oct 21 2008 - 21:38:15 EST


On Wed, 22 Oct 2008 10:24:04 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:

> Andrew, this is a fix to "x86 cannot boot if memcg is enabled" problem in Linus's git-tree,0
> fix to "memcg: allocate all page_cgroup at boot" patch.
>
> Thank you for all helps!
> (*) I and Balbir tested this. other testers are welcome :)
> -Kame
> ==
>
> page_cgroup_init() is called from mem_cgroup_init(). But at this
> point, we cannot call alloc_bootmem().
> (and this caused panic at boot.)
>
> This patch moves page_cgroup_init() to init/main.c.
>
> Time table is following:
> ==
> parse_args(). # we can trust mem_cgroup_subsys.disabled bit after this.
> ....
> cgroup_init_early() # "early" init of cgroup.
> ....
> setup_arch() # memmap is allocated.
> ...
> page_cgroup_init();
> mem_init(); # we cannot call alloc_bootmem after this.
> ....
> cgroup_init() # mem_cgroup is initialized.
> ==
>
> Before page_cgroup_init(), mem_map must be initialized. So,
> I added page_cgroup_init() to init/main.c directly.
>
> (*) maybe this is not very clean but
> - cgroup_init_early() is too early
> - in cgroup_init(), we have to use vmalloc instead of alloc_bootmem().
> use of vmalloc area in x86-32 is important and we should avoid very large
> vmalloc() in x86-32. So, we want to use alloc_bootmem() and added page_cgroup_init()
> directly to init/main.c
>
> Acked-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
> Tested-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>
> init/main.c | 2 ++
> mm/memcontrol.c | 1 -
> mm/page_cgroup.c | 35 ++++++++++++++++++++++++++++-------
> 3 files changed, 30 insertions(+), 8 deletions(-)
>
> Index: linux-2.6/init/main.c
> ===================================================================
> --- linux-2.6.orig/init/main.c
> +++ linux-2.6/init/main.c
> @@ -62,6 +62,7 @@
> #include <linux/signal.h>
> #include <linux/idr.h>
> #include <linux/ftrace.h>
> +#include <linux/page_cgroup.h>
>
> #include <asm/io.h>
> #include <asm/bugs.h>
> @@ -647,6 +648,7 @@ asmlinkage void __init start_kernel(void
> vmalloc_init();
> vfs_caches_init_early();
> cpuset_init_early();
> + page_cgroup_init();
> mem_init();
> enable_debug_pagealloc();
> cpu_hotplug_init();
> Index: linux-2.6/mm/memcontrol.c
> ===================================================================
> --- linux-2.6.orig/mm/memcontrol.c
> +++ linux-2.6/mm/memcontrol.c
> @@ -1088,7 +1088,6 @@ mem_cgroup_create(struct cgroup_subsys *
> int node;
>
> if (unlikely((cont->parent) == NULL)) {
> - page_cgroup_init();
> mem = &init_mem_cgroup;
> } else {
> mem = mem_cgroup_alloc();
> Index: linux-2.6/mm/page_cgroup.c
> ===================================================================
> --- linux-2.6.orig/mm/page_cgroup.c
> +++ linux-2.6/mm/page_cgroup.c
> @@ -4,7 +4,12 @@
> #include <linux/bit_spinlock.h>
> #include <linux/page_cgroup.h>
> #include <linux/hash.h>
> +#include <linux/slab.h>
> #include <linux/memory.h>
> +#include <linux/cgroup.h>
> +
> +extern struct cgroup_subsys mem_cgroup_subsys;

no no bad! evil! unclean!

Didn't the linux/cgroup.h -> linux/cgroup_subsys..h inclusion already
declare this for us?

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/