Re: [PATCH] node meminfo Active & Inactive pages to Kbytes

[John Blackwood <john.blackwood@ccur.com>]

Andrew Morton wrote:
> On Thu, 3 Jul 2008 10:35:57 -0400
> John Blackwood <john.blackwood@ccur.com> wrote:
> 
>> Hi Andrew and Andi,
>>
>> We found a minor bug in the output of
>> /sys/devices/system/node/node[n]/meminfo
>> where the Active and Inactive values are in pages instead of Kbytes.
>>
>> Looks like this occurred back in 2.6.20 when the code was changed
>> over to use node_page_state().
>>
>> Thanks.
>>
>> --- linux.2.6.26-rc8/drivers/base/node.c      2008-07-03 09:26:01.000000000 -0400
>> +++ new/drivers/base/node.c   2008-07-03 09:25:45.000000000 -0400
>> @@ -84,8 +84,8 @@ static ssize_t node_read_meminfo(struct
>>                      nid, K(i.totalram),
>>                      nid, K(i.freeram),
>>                      nid, K(i.totalram - i.freeram),
>> -                    nid, node_page_state(nid, NR_ACTIVE),
>> -                    nid, node_page_state(nid, NR_INACTIVE),
>> +                    nid, K(node_page_state(nid, NR_ACTIVE)),
>> +                    nid, K(node_page_state(nid, NR_INACTIVE)),
>>   #ifdef CONFIG_HIGHMEM
>>                      nid, K(i.totalhigh),
>>                      nid, K(i.freehigh),
> 
> ug.  After all that time there might be applications out there which
> use the existing numbers and work around the kernel bug.  Which we'll
> break if we fix it.

true.  our tool that looks at these numbers is going to be changed to 
optionally multiply the values by 4 based on the kernel revision/version 
number once this change makes it into the main tree.

> otoh, who the heck cares about the per-node active and inactive page
> counts?

   :-)


> I guess we just fix this, backport the fix as far as we can and
> apologise for any fallout.  Not that there's likely to be any.
> 
o.k. Thanks.

> Please do remember to add a Signed-off-by: for kernel patches.
> 

o.k. Sorry about that.