Re: [PATCH v4 03/11] memcg: create extensible page stat update routines

[Ciju Rajan K <ciju@linux.vnet.ibm.com>]

Greg Thelen wrote:
> Ciju Rajan K <ciju@linux.vnet.ibm.com> writes:
>
>   
>> Greg Thelen wrote:
>>     
>>> Replace usage of the mem_cgroup_update_file_mapped() memcg
>>> statistic update routine with two new routines:
>>> * mem_cgroup_inc_page_stat()
>>> * mem_cgroup_dec_page_stat()
>>>
>>> As before, only the file_mapped statistic is managed.  However,
>>> these more general interfaces allow for new statistics to be
>>> more easily added.  New statistics are added with memcg dirty
>>> page accounting.
>>>
>>> Signed-off-by: Greg Thelen <gthelen@google.com>
>>> Signed-off-by: Andrea Righi <arighi@develer.com>
>>> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>>> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
>>> ---
>>> Changelog since v1:
>>> - Rename (for clarity):
>>>   - mem_cgroup_write_page_stat_item -> mem_cgroup_page_stat_item
>>>   - mem_cgroup_read_page_stat_item -> mem_cgroup_nr_pages_item
>>>
>>>  include/linux/memcontrol.h |   31 ++++++++++++++++++++++++++++---
>>>  mm/memcontrol.c            |   16 +++++++---------
>>>  mm/rmap.c                  |    4 ++--
>>>  3 files changed, 37 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
>>> index 159a076..067115c 100644
>>> --- a/include/linux/memcontrol.h
>>> +++ b/include/linux/memcontrol.h
>>> @@ -25,6 +25,11 @@ struct page_cgroup;
>>>  struct page;
>>>  struct mm_struct;
>>>
>>> +/* Stats that can be updated by kernel. */
>>> +enum mem_cgroup_page_stat_item {
>>> +	MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
>>> +};
>>> +
>>>  extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
>>>  					struct list_head *dst,
>>>  					unsigned long *scanned, int order,
>>> @@ -121,7 +126,22 @@ static inline bool mem_cgroup_disabled(void)
>>>  	return false;
>>>  }
>>>
>>> -void mem_cgroup_update_file_mapped(struct page *page, int val);
>>> +void mem_cgroup_update_page_stat(struct page *page,
>>> +				 enum mem_cgroup_page_stat_item idx,
>>> +				 int val);
>>> +
>>> +static inline void mem_cgroup_inc_page_stat(struct page *page,
>>> +					    enum mem_cgroup_page_stat_item idx)
>>> +{
>>> +	mem_cgroup_update_page_stat(page, idx, 1);
>>> +}
>>> +
>>> +static inline void mem_cgroup_dec_page_stat(struct page *page,
>>> +					    enum mem_cgroup_page_stat_item idx)
>>> +{
>>> +	mem_cgroup_update_page_stat(page, idx, -1);
>>> +}
>>> +
>>>  unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
>>>  						gfp_t gfp_mask);
>>>  u64 mem_cgroup_get_limit(struct mem_cgroup *mem);
>>> @@ -293,8 +313,13 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
>>>  {
>>>  }
>>>
>>> -static inline void mem_cgroup_update_file_mapped(struct page *page,
>>> -							int val)
>>> +static inline void mem_cgroup_inc_page_stat(struct page *page,
>>> +					    enum mem_cgroup_page_stat_item idx)
>>> +{
>>> +}
>>> +
>>> +static inline void mem_cgroup_dec_page_stat(struct page *page,
>>> +					    enum mem_cgroup_page_stat_item idx)
>>>  {
>>>  }
>>>
>>> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
>>> index 9a99cfa..4fd00c4 100644
>>> --- a/mm/memcontrol.c
>>> +++ b/mm/memcontrol.c
>>> @@ -1592,7 +1592,8 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
>>>   * possibility of race condition. If there is, we take a lock.
>>>   */
>>>
>>>   
>>>       
>> Greg,
>>
>> I am not seeing the function mem_cgroup_update_file_stat() in the latest mmotm
>> 2010-10-22-16-36.
>> So not able to apply this patch. Tried couple of times cloning the entire mmotm
>> git repository. But no luck.
>> Tried in the web interface http://git.zen-kernel.org/mmotm/tree/mm/memcontrol.c
>> also. It is not there.
>> Surprisingly git log doesn't show any recent changes to mm/memcontrol.c. Am I
>> missing something?
>> I could see this function in the mainline linux 2.6 git tree.
>>
>> -Ciju
>>     
>
> mem_cgroup_update_file_mapped() was renamed to
> mem_cgroup_update_file_stat() in
> http://userweb.kernel.org/~akpm/mmotm/broken-out/memcg-generic-filestat-update-interface.patch
>
> I also do not see this in the mmotm git repo.  However, if I manually
> apply the mmotm patches to v2.6.36 using quilt then I see the expected
> patched memcontrol.c.  I am not sure why the zen-kernel.org git mmotm
> repo differs from a mmotm patched mainline 2.6.36.
>
> Here is my procedure using quilt to patch mainline:
>
> # Checkout 2.6.36 mainline
> $ git checkout v2.6.36
>
> # Confirm mainline 2.6.36 does not have mem_cgroup_update_file_stat()
> $ grep mem_cgroup_update_file_stat -r mm
>
> # Apply patches
> $ curl http://userweb.kernel.org/~akpm/mmotm/broken-out.tar.gz | tar -xzf -
> $ export QUILT_PATCHES=broken-out
> $ quilt push -aq
> ...
> Now at patch memblock-add-input-size-checking-to-memblock_find_region-fix.patch
>
> # Now the memcontrol contains mem_cgroup_update_file_stat()
> $ grep mem_cgroup_update_file_stat -r mm
> mm/memcontrol.c:static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
> mm/memcontrol.c:        mem_cgroup_update_file_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, val);
>
>   
Reviewed-by: Ciju Rajan K <ciju@linux.vnet.ibm.com>
>>> -static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
>>> +void mem_cgroup_update_page_stat(struct page *page,
>>> +				 enum mem_cgroup_page_stat_item idx, int val)
>>>  {
>>>  	struct mem_cgroup *mem;
>>>  	struct page_cgroup *pc = lookup_page_cgroup(page);
>>> @@ -1615,30 +1616,27 @@ static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
>>>  			goto out;
>>>  	}
>>>
>>> -	this_cpu_add(mem->stat->count[idx], val);
>>> -
>>>  	switch (idx) {
>>> -	case MEM_CGROUP_STAT_FILE_MAPPED:
>>> +	case MEMCG_NR_FILE_MAPPED:
>>>  		if (val > 0)
>>>  			SetPageCgroupFileMapped(pc);
>>>  		else if (!page_mapped(page))
>>>  			ClearPageCgroupFileMapped(pc);
>>> +		idx = MEM_CGROUP_STAT_FILE_MAPPED;
>>>  		break;
>>>  	default:
>>>  		BUG();
>>>  	}
>>>
>>> +	this_cpu_add(mem->stat->count[idx], val);
>>> +
>>>  out:
>>>  	if (unlikely(need_unlock))
>>>  		unlock_page_cgroup(pc);
>>>  	rcu_read_unlock();
>>>  	return;
>>>  }
>>> -
>>> -void mem_cgroup_update_file_mapped(struct page *page, int val)
>>> -{
>>> -	mem_cgroup_update_file_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, val);
>>> -}
>>> +EXPORT_SYMBOL(mem_cgroup_update_page_stat);
>>>
>>>  /*
>>>   * size of first charge trial. "32" comes from vmscan.c's magic value.
>>> diff --git a/mm/rmap.c b/mm/rmap.c
>>> index 1a8bf76..a66ab76 100644
>>> --- a/mm/rmap.c
>>> +++ b/mm/rmap.c
>>> @@ -911,7 +911,7 @@ void page_add_file_rmap(struct page *page)
>>>  {
>>>  	if (atomic_inc_and_test(&page->_mapcount)) {
>>>  		__inc_zone_page_state(page, NR_FILE_MAPPED);
>>> -		mem_cgroup_update_file_mapped(page, 1);
>>> +		mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
>>>  	}
>>>  }
>>>
>>> @@ -949,7 +949,7 @@ void page_remove_rmap(struct page *page)
>>>  		__dec_zone_page_state(page, NR_ANON_PAGES);
>>>  	} else {
>>>  		__dec_zone_page_state(page, NR_FILE_MAPPED);
>>> -		mem_cgroup_update_file_mapped(page, -1);
>>> +		mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
>>>  	}
>>>  	/*
>>>  	 * It would be tidy to reset the PageAnon mapping here,
>>>   
>>>       

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