Re: [PATCH v2 2/2] fs: proc: Include cma info in proc/meminfo

[Gioh Kim <gioh.kim@lge.com>]

2014-10-24 ?AEA 5:57, PINTU KUMAR  3/4 ' +-U:
> Hi,
> 
> ----- Original Message -----
>> From: Gioh Kim <gioh.kim@lge.com>
>> To: Pintu Kumar <pintu.k@samsung.com>; akpm@linux-foundation.org;
> riel@redhat.com; aquini@redhat.com; paul.gortmaker@windriver.com;
> jmarchan@redhat.com; lcapitulino@redhat.com;
> kirill.shutemov@linux.intel.com; m.szyprowski@samsung.com;
> aneesh.kumar@linux.vnet.ibm.com; iamjoonsoo.kim@lge.com; mina86@mina86.com;
> lauraa@codeaurora.org; mgorman@suse.de; rientjes@google.com; hannes@cmpxchg.
> org; vbabka@suse.cz; sasha.levin@oracle.com; linux-kernel@vger.kernel.org;
> linux-mm@kvack.org
>> Cc: pintu_agarwal@yahoo.com; cpgs@samsung.com; vishnu.ps@samsung.com;
> rohit.kr@samsung.com; ed.savinay@samsung.com
>> Sent: Thursday, 23 October 2014 5:49 AM
>> Subject: Re: [PATCH v2 2/2] fs: proc: Include cma info in proc/meminfo
>>
>>
>>
>> 2014-10-22 ?AEA 11:06, Pintu Kumar  3/4 ' +-U:
>>> This patch include CMA info (CMATotal, CMAFree) in /proc/meminfo.
>>> Currently, in a CMA enabled system, if somebody wants to know the
>>> total CMA size declared, there is no way to tell, other than the dmesg
>>> or /var/log/messages logs.
>>> With this patch we are showing the CMA info as part of meminfo, so that
>>> it can be determined at any point of time.
>>> This will be populated only when CMA is enabled.
>>>
>>> Below is the sample output from a ARM based device with RAM:512MB and
>> CMA:16MB.
>>>
>>> MemTotal:        471172 kB
>>> MemFree:          111712 kB
>>> MemAvailable:    271172 kB
>>> .
>>> .
>>> .
>>> CmaTotal:          16384 kB
>>> CmaFree:            6144 kB
>>>
>>> This patch also fix below checkpatch errors that were found during these
>> changes.
>>
>> Why don't you split patch for it?
>> I think there's a rule not to mix separate patchs.
>>
> 
> Last time when we submitted separate patches for checkpatch errors, it was
> suggested to
> Include these kinds of fixes along with some meaningful patches together.
> So, we included it in same patch.
> 
>>>
>>> ERROR: space required after that ',' (ctx:ExV)
>>> 199: FILE: fs/proc/meminfo.c:199:
>>> +      ,atomic_long_read(&num_poisoned_pages) << (PAGE_SHIFT -
>> 10)
>>>            ^
>>>
>>> ERROR: space required after that ',' (ctx:ExV)
>>> 202: FILE: fs/proc/meminfo.c:202:
>>> +      ,K(global_page_state(NR_ANON_TRANSPARENT_HUGEPAGES) *
>>>            ^
>>>
>>> ERROR: space required after that ',' (ctx:ExV)
>>> 206: FILE: fs/proc/meminfo.c:206:
>>> +      ,K(totalcma_pages)
>>>            ^
>>>
>>> total: 3 errors, 0 warnings, 2 checks, 236 lines checked
>>>
>>> Signed-off-by: Pintu Kumar <pintu.k@samsung.com>
>>> Signed-off-by: Vishnu Pratap Singh <vishnu.ps@samsung.com>
>>> ---
>>>    fs/proc/meminfo.c |  15 +++++++++++++--
>>>    1 file changed, 13 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
>>> index aa1eee0..d3ebf2e 100644
>>> --- a/fs/proc/meminfo.c
>>> +++ b/fs/proc/meminfo.c
>>> @@ -12,6 +12,9 @@
>>>    #include <linux/vmstat.h>
>>>    #include <linux/atomic.h>
>>>    #include <linux/vmalloc.h>
>>> +#ifdef CONFIG_CMA
>>> +#include <linux/cma.h>
>>> +#endif
>>>    #include <asm/page.h>
>>>    #include <asm/pgtable.h>
>>>    #include "internal.h"
>>> @@ -138,6 +141,10 @@ static int meminfo_proc_show(struct seq_file *m,
> void
>> *v)
>>>    #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>>            "AnonHugePages:  %8lu kB\n"
>>>    #endif
>>> +#ifdef CONFIG_CMA
>>> +        "CmaTotal:      %8lu kB\n"
>>> +        "CmaFree:        %8lu kB\n"
>>> +#endif
>>>            ,
>>>            K(i.totalram),
>>>            K(i.freeram),
>>> @@ -187,12 +194,16 @@ static int meminfo_proc_show(struct seq_file *m,
> void
>> *v)
>>>            vmi.used >> 10,
>>>            vmi.largest_chunk >> 10
>>>    #ifdef CONFIG_MEMORY_FAILURE
>>> -        ,atomic_long_read(&num_poisoned_pages) << (PAGE_SHIFT -
>> 10)
>>> +        , atomic_long_read(&num_poisoned_pages) << (PAGE_SHIFT -
>> 10)
>>>    #endif
>>>    #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>> -        ,K(global_page_state(NR_ANON_TRANSPARENT_HUGEPAGES) *
>>> +        , K(global_page_state(NR_ANON_TRANSPARENT_HUGEPAGES) *
>>>              HPAGE_PMD_NR)
>>>    #endif
>>> +#ifdef CONFIG_CMA
>>> +        , K(totalcma_pages)
>>> +        , K(global_page_state(NR_FREE_CMA_PAGES))
>>> +#endif
>>>            );
>>
>> Just for sure, are zoneinfo and pagetypeinfo not suitable?
>>
> 
> I think zoneinfo shows only current free cma pages.
> Same is the case with vmstat.
> # cat /proc/zoneinfo | grep cma
>      nr_free_cma  2560
> # cat /proc/vmstat | grep cma
> nr_free_cma 2560

We could add a line to show total cma pages like following and add it all.
# cat /proc/zoneinfo | grep cma
      nr_total_cma XXXX
      nr_free_cma  2560

Yes. each zone can have cma area and it is annoying to add it all.
But IMO it is rare and not difficult.
And I think it'd better that zoneinfo has nr_total_cma line.

I think you already considered my thoughts and choosed /proc/meminfo for a certain reason.
Why is /proc/meminfo better?

Andrew already accepted it. I'm not against your idea. Just curious.

> 
>> I don't know HOTPLUG feature so I'm just asking for sure.
>> Does HOTPLUG not need printing message like this?
>>
> 
> Sorry, I am also not sure what hotplug feature you are referring to.

I mean "memory hotplug" feature.
Forget it ;-)

> 
>> Thanks a lot.
>>
>>
>>>    
>>>        hugetlb_report_meminfo(m);
>>>
>>
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