On Mon, Oct 05, 2015 at 01:21:43AM +0300, Vladimir Davydov wrote:
> Before the previous patch, __mem_cgroup_from_kmem had to handle two
> types of kmem - slab pages and pages allocated with alloc_kmem_pages -
> differently, because slab pages did not store information about owner
> memcg in the page struct. Now we can unify it. Since after it, this
> function becomes tiny we can fold it into mem_cgroup_from_kmem.
>
> Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
> ---
> include/linux/memcontrol.h | 7 ++++---
> mm/memcontrol.c | 18 ------------------
> 2 files changed, 4 insertions(+), 21 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 8a9b7a798f14..0e2e039609d1 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -769,8 +769,6 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg)
> struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep);
> void __memcg_kmem_put_cache(struct kmem_cache *cachep);
>
> -struct mem_cgroup *__mem_cgroup_from_kmem(void *ptr);
> -
> static inline bool __memcg_kmem_bypass(gfp_t gfp)
> {
> if (!memcg_kmem_enabled())
> @@ -832,9 +830,12 @@ static __always_inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
>
> static __always_inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr)
> {
> + struct page *page;
> +
> if (!memcg_kmem_enabled())
> return NULL;
> - return __mem_cgroup_from_kmem(ptr);
> + page = virt_to_head_page(ptr);
> + return page->mem_cgroup;
> }
virt_to_head_page() is defined in <linux/mm.h> but you don't include it,
and the commit breaks build for me (on v4.3-rc5-mmotm-2015-10-15-15-20).
CC arch/x86/kernel/asm-offsets.s
In file included from /home/kas/linux/mm/include/linux/swap.h:8:0,
from /home/kas/linux/mm/include/linux/suspend.h:4,
from /home/kas/linux/mm/arch/x86/kernel/asm-offsets.c:12:
/home/kas/linux/mm/include/linux/memcontrol.h: In function â??mem_cgroup_from_kmemâ??:
/home/kas/linux/mm/include/linux/memcontrol.h:841:9: error: implicit declaration of function â??virt_to_head_pageâ?? [-Werror=implicit-function-declaration]
page = virt_to_head_page(ptr);
^
/home/kas/linux/mm/include/linux/memcontrol.h:841:7: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
page = virt_to_head_page(ptr);
^
In file included from /home/kas/linux/mm/include/linux/suspend.h:8:0,
from /home/kas/linux/mm/arch/x86/kernel/asm-offsets.c:12:
/home/kas/linux/mm/include/linux/mm.h: At top level:
/home/kas/linux/mm/include/linux/mm.h:452:28: error: conflicting types for â??virt_to_head_pageâ??
static inline struct page *virt_to_head_page(const void *x)
^
In file included from /home/kas/linux/mm/include/linux/swap.h:8:0,
from /home/kas/linux/mm/include/linux/suspend.h:4,
from /home/kas/linux/mm/arch/x86/kernel/asm-offsets.c:12:
/home/kas/linux/mm/include/linux/memcontrol.h:841:9: note: previous implicit declaration of â??virt_to_head_pageâ?? was here
page = virt_to_head_page(ptr);
^
cc1: some warnings being treated as errors
The patch below fixes it for me (and for allmodconfig on x86-64), but I'm not
sure if it have any side effects on other configurations.
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 47677acb4516..e8e52e502c20 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -26,6 +26,7 @@
#include <linux/page_counter.h>
#include <linux/vmpressure.h>
#include <linux/eventfd.h>
+#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/writeback.h>
--
Kirill A. Shutemov
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