slabtop command is a Linux utility that displays real-time information about the kernel slab memory cache. In Linux, the slab allocator is a memory management subsystem that manages small, frequently allocated kernel objects such as data structures, buffers, and caches. The
slabtop command provides a detailed overview of the slab cache, including the number of objects, their size, and the total amount of memory used by each cache.
slabtop command is used to display information about the kernel slab memory cache. To use the
slabtop command, simply type
slabtop in the terminal. The output will display the following columns:
- Cache: The name of the cache
- Num: The number of objects in the cache
- Alloc: The total amount of memory allocated by the cache
- Free: The total amount of free memory in the cache
- Total: The total size of the cache
- Size: The size of each object in the cache
- Slabs: The number of slabs used by the cache
- Depth: The depth of the cache
Here is an example of the output of the
OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 1006 978 97% 0.51K 22 46 7040K buffer_head 7104 7104 100% 0.03K 44 161 704K dentry 4096 4096 100% 0.02K 32 128 512K ext4_inode_cache 1024 992 97% 0.06K 16 64 256K kmalloc-64 2048 2048 100% 0.03K 16 128 256K kmalloc-32 1024 1024 100% 0.03K 8 128 128K kmalloc-16 3072 3072 100% 0.01K 24 128 96K kmalloc-8 512 512 100% 0.03K 4 128 64K kmalloc-32percpu 1024 1024 100% 0.02K 8 128 32K kmalloc-16percpu 2048 2048 100% 0.01K 16 128 32K kmalloc-8percpu
slabtop command can be used to monitor the memory usage of the kernel slab cache in real-time. This can be useful for identifying memory leaks or other issues that may be impacting system performance.
slabtop command has several options that can be used to customize the output. The available options are:
||Sort output by the specified column (e.g.,
||Only display caches that match the specified regular expression|
||Display output in bytes instead of kilobytes|
||Set the delay between updates (in seconds)|
If you are experiencing issues with high memory usage or performance problems, the
slabtop command can be a useful tool for identifying the source of the problem. Here are some troubleshooting tips for using the
- Look for caches with a high number of objects or a large amount of memory allocated. These may be the source of memory leaks or other issues.
- Use the
-soption to sort the output by the column that is most relevant to your issue. For example, if you are experiencing performance issues, you may want to sort by the number of objects to identify caches that are being accessed frequently.
- Use the
-ooption to filter the output to only display caches that match a specific regular expression. This can be useful if you are looking for a specific cache or want to exclude certain caches from the output.
slabtopcommand requires root privileges to run.
slabtopcommand is only available on Linux systems that use the slab allocator. Some newer Linux systems may use the slub allocator instead, which does not support the