• Slides

Download and unzip the tasks archive sesiune-06 on the virtual machine.

1. Memory limits (1)
   • Use the code in 1-mem/ directory and figure out the maximum chunk size that can be allocated using kmalloc.
   • Start by allocating a chunk of size 1K, and double the memory allocated at each iteration. Stop when kmalloc fails.
2. Memory limits (2)
   • Use the code in 1-mem/ directory and figure out the maximum amount of memory that can be allocated in tne system.
   • Allocate memory chunks of 1K until the system gets Out of Memory.
3. Memory caches
   • Check the code in 2-cache/ directory and see how memory caches are created. Following the example from cache.c allocate 2048 penguin objects.
   • Analyze the output for the following commands slabtop and cat /proc/slabinfo in respect with penguin structure.
4. The curse of sleeping
   • Use the skeleton code from 3-context/ and fill in the code in context.c so that:
     • use kmalloc function with GFP_KERNEL flag, protect the allocation using a spin_lock.
     • use kmalloc function with GFP_ATOMIC flag, protect the allocation using a spin_lock.
     • replace kmalloc function with schedule_timeout.
5. Memory mappings
   • Use the skeleton code from 4-mmap/ and fill in the code in kmmap.c so that:
     • /dev/mmap has support for memory mapping
     • Implement function my_map in kmmap.c. Use mmap as an example.
     • Follow TODO's lines in kmmap.c
   • Create an userspace program mmap.c that mmaps /dev/my_mmap and reads a page.
   • Check mmap.c memory mapped areas using pmap.