Hello everyone, I am experiencing a problem using my Linux 2.6.33 and doing this networking test using ab, a tool from Apache which helps me to benchmark the performances of a website, actually I am using that as a tool for generate a lot of traffic and TCP connections. My topology is : [AB PC] <==> [LINUX] <==> [WEBSITE] I run ab like that ab -c 300 -n 20000 http://10.0.0.103/index.html and my problem is that after some time my system will reboot to a low memory condition, this is caused by the watchdog I have installed in my system, I tried to monitor my applications but I did not see any growth in the memory usage then I started to investigate if something is happening in the Kernel, using slab top I have got: OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 33392 33392 100% 1.00K 8348 4 33392K size-1024 3716 3716 100% 4.00K 3716 1 14864K size-4096 34238 33899 99% 0.20K 1802 19 7208K skbuff_head_cache 547 538 98% 8.00K 547 1 4376K size-8192 12488 12488 100% 0.27K 892 14 3568K nf_conntrack_c0ca4b0c 12990 12990 100% 0.12K 433 30 1732K size-128 2211 2211 100% 0.34K 201 11 804K inode_cache 11387 11368 99% 0.06K 193 59 772K size-64 41 41 100% 16.00K 41 1 656K size-16384 4 4 100% 128.00K 4 1 512K size-131072 2782 2702 97% 0.15K 107 26 428K dentry 4982 4957 99% 0.07K 94 53 376K sysfs_dir_cache 8814 8558 97% 0.03K 78 113 312K size-32 400 400 100% 0.50K 50 8 200K size-512 1540 1255 81% 0.11K 44 35 176K vm_area_struct 432 423 97% 0.30K 36 12 144K radix_tree_node The first line 33392 33392 100% 1.00K 8348 4 33392K size-1024 tell me that size-1024 is using quite a lot of memory, how can I understand who is using that memory ? Thanks in advance, Pietro