Hi, Everyone
I ran across the following novel case similar to memory leak in linux-4.1
stable when allocating
memory object by kmem_cache_alloc. it rarely can be reproduced.
I create a specific mempool with 24k size based on the slab. it can not be
merged with
other kmem cache. I record the allocation and free usage by atomic_add/sub.
After a while,
I watch the specific slab consume most of total memory. After halting the
code execution.
The counter of allocation and free is equal. Therefore, I am sure that module
have released
all meory resource. but the statistic of specific slab is very high but stable
by checking /proc/slabinfo.
but It is strange that the specific slab will free get back all memory when
unregister the module.
I got the following information from specific slab data structure when halt the
module execution.
kmem_cache_node
kmem_cache
nr_partial = 1,
min_partial = 7
partial = {
cpu_partial = 2
next = 0xffff7c00085cae20 object_size =
24576
prev = 0xffff7c00085cae20
},
nr_slabs = {
counter = 365610
},
total_objects = {
counter = 365610
},
full = {
next = 0xffff8013e44f75f0,
prev = 0xffff8013e44f75f0
},
>From the above restricted information , we can know that the node full list is
>empty. and partial list only
have a slab. A slab contain a object. I think that most of slab stay in the
cpu_partial
list even though it seems to be impossible theoretically. because I come to
the conclusion based on the case
that slab take up the memory will be release when unregister the moudle.
but I check the code(mm/slub.c) carefully . I can not find any clue to prove my
assumption.
I will be appreciate if anyone have any idea about the case.
Thanks
zhong jiang
