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

[Christoph Lameter (Ampere)]

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@xxxxxxxxxx>
> > > ---
> > >  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?