slab/kernel memory problem

[Alexander Lazarevich]

We have a RHEL4-AS 64bit system, and a FC364bit system. Both running most 
recent kernels.

We've got bad memory problems. The kernel is sucking up quite a bit of 
memory, check out Slab in meminfo:

[root at hostname ~]# cat /proc/meminfo
MemTotal:      8078596 kB
MemFree:        486480 kB
Buffers:       1075532 kB
Cached:         527284 kB
SwapCached:       1384 kB
Active:        2120352 kB
Inactive:      1019628 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:      8078596 kB
LowFree:        486480 kB
SwapTotal:     2096472 kB
SwapFree:      2053372 kB
Dirty:              28 kB
Writeback:           0 kB
Mapped:        1564776 kB
Slab:          4424180 kB
CommitLimit:   6135768 kB
Committed_AS:  1836712 kB
PageTables:       9952 kB
VmallocTotal: 34359738367 kB
VmallocUsed:      1356 kB
VmallocChunk: 34359736951 kB
HugePages_Total:     0
HugePages_Free:      0
Hugepagesize:     2048 kB


Then, slabtop is showing what is using all that slab mem:

  Active / Total Objects (% used)    : 9028210 / 9033666 (99.9%)
  Active / Total Slabs (% used)      : 1105829 / 1105834 (100.0%)
  Active / Total Caches (% used)     : 94 / 135 (69.6%)
  Active / Total Size (% used)       : 108142.02K / 108819.82K (99.4%)
  Minimum / Average / Maximum Object : 0.02K / 0.01K / 128.00K

   OBJS ACTIVE  USE OBJ SIZE  SLABS OBJ/SLAB CACHE SIZE NAME
4181455 4181452  99%    0.78K 836291        5   3345164K ext3_inode_cache
4129011 4129007  99%    0.23K 242883       17    971532K dentry_cache

Why in the heck is the system trying to use all this memory to cache 
ext3 inodes? This happens on both FC364bit and RHEL4-AS64bit.

I've search google and bugzilla, couldn't find anything.

Anyone see this as well?

Thanks!

Alex