Re: [PATCH] mm/slab: Add slabreclaim flag to slabinfo

["Christoph Lameter (Ampere)" <cl@linux.com>]

On Mon, 5 Feb 2024, Vlastimil Babka wrote:

> On 2/4/24 14:09, Greg KH wrote:
>> On Wed, Jan 31, 2024 at 05:44:42PM +0800, Fangzheng Zhang wrote:
>>> In order to enhance slab debugging, we add slabreclaim flag to
>>> slabinfo. Slab type is also an important analysis point in slabinfo
>>> for per slab, when various problems such as memory leaks or memory
>>> statistics occur.
>>>
>>> Signed-off-by: Fangzheng Zhang <fangzheng.zhang@unisoc.com>
>>> ---
>>>  mm/slab_common.c | 7 ++++---
>>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/mm/slab_common.c b/mm/slab_common.c
>>> index 238293b1dbe1..aeeb2bfe6dda 100644
>>> --- a/mm/slab_common.c
>>> +++ b/mm/slab_common.c
>>> @@ -1038,7 +1038,7 @@ static void print_slabinfo_header(struct seq_file *m)
>>>  	seq_puts(m, "slabinfo - version: 2.1\n");
>>>  	seq_puts(m, "# name            <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
>>>  	seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
>>> -	seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
>>> +	seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail> <slabreclaim>");
>>
>> Doesn't this change the slabinfo version number above?  Where is this
>> change documented so that userspace knows about it?

I have never seen such a document. I would suggest incrementing the 
version to 2.2 since there is a minor extension of the format.

I tried to remove /proc/slabinfo in the past and have people use the more 
versatile /sys/kernel/slab interface. But /proc/slabinfo has a long 
legacy.

Could we mark /proc/slabinfo as deprecated and recommend the use of
either sysfs directly or use of the "slabinfo" tool that we have 
been providing in linux/tools/mm for a long time?