Hi Andrew,

Could you please consider including this patch into your mm tree ?

This patch collects data about how a shrinkable cache is behaving
over time. The number of objects scanned for shrinking
the cache and the actual number of objects freed are reported by
this patch as part of /proc/slabinfo. I have verified that adding
addtional elements to /proc/slabinfo isn't breaking slabtop.

I have made this patch on suggestions from Marcelo and he feels that
it is useful to have this in mm/mainline. This work started as an attempt
to break the slabs_scanned(from /proc/vmstat) into meaningful pieces
to reflect how individual cache behaves wrt memory reclaim.

A typical output from /proc/slabinfo after this patch looks like this:

[root@llm09 ~]# grep shrinker /proc/slabinfo
# name            <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>
 : tunables <limit> <batchcount> <sharedfactor> : slabdata <active_slabs> <num_s
labs> <sharedavail> : shrinker stat <nr requested> <nr freed>
ext3_xattr             0      0     48   78    1 : tunables  120   60    8 : sla
bdata      0      0      0 : shrinker stat       0       0
d_cursor               0      0     64   59    1 : tunables  120   60    8 : sla
bdata      0      0      0 : shrinker stat       0       0
dquot                  0      0    160   24    1 : tunables  120   60    8 : sla
bdata      0      0      0 : shrinker stat       0       0
inode_cache         1262   1400    400   10    1 : tunables   54   27    8 : sla
bdata    140    140      0 : shrinker stat  376704  380400
dentry_cache       10449  10504    152   26    1 : tunables  120   60    8 : sla
bdata    404    404      0 : shrinker stat  859136  401700

Note: mbcache maintains multiple caches with a single shrinker routine.
Hence with this patch, all caches which are part of mbcache (like ext3_xattr
above) will display the combined shrinker statistics of mbcache and not
the shrinker attempts of individual caches. Or should I just drop the
stats collection from mbcache ?

Regards,
Bharata.