Am Montag, 22. November 2010 schrieben Sie: > > We see that Slab uses most of the memory. And within slab nearly > > everything is > > > > used for ext4_alloc_context. There is the output of slabtop: > > Active / Total Objects (% used) : 364597 / 1070670469 (0.0%) > > Active / Total Slabs (% used) : 52397 / 39688960 (0.1%) > > Active / Total Caches (% used) : 107 / 193 (55.4%) > > Active / Total Size (% used) : 159579.25K / 150697605.41K (0.1%) > > Minimum / Average / Maximum Object : 0.02K / 0.14K / 4096.00K > > > > OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME > > > > 1070187012 0 0% 0.14K 39636556 27 158546224K > > ext4_alloc_context > > and it's all unused... (inactive) > > To make matters worse drop_caches doesn't touch the slabs, IIRC, but you > might try: echo 3 > /proc/sys/vm/drop_caches I tried it and it did not improve anything. > > I see no reason why ext4 should use so much memory. What is it used for? > > And how can I release it to get it used for my processes. > > You may need to reboot, or at best unmount ext4 filesystems and/or rmmod > the ext4 module, if the drop_caches trick doesn't work. > > The fact that this doesn't get reclaimed seems to point to a problem > with the vm though, I think (aside from the craziness of ext4 using > this slab so heavily without my patch...) I see the problem for the first time and I do not know whether it is reproducable. We have several similar machines with similar workloads but none has shown such a problem till now. I'm going to reboot the machine. If it shows the problem again I will try a newer kernel and then the patch. Some workload will be lost, but the machine did not do anything useful for three days now :) Thanks, Christoph -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
