Re: [PATCH v2 1/4] memcg: Track exported dma-buffers

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon 23-01-23 19:17:23, T.J. Mercier wrote:
> When a buffer is exported to userspace, use memcg to attribute the
> buffer to the allocating cgroup until all buffer references are
> released.

Is there any reason why this memory cannot be charged during the
allocation (__GFP_ACCOUNT used)?
Also you do charge and account the memory but underlying pages do not
know about their memcg (this is normally done with commit_charge for
user mapped pages). This would become a problem if the memory is
migrated for example. This also means that you have to maintain memcg
reference outside of the memcg proper which is not really nice either.
This mimicks tcp kmem limit implementation which I really have to say I
am not a great fan of and this pattern shouldn't be coppied.

Also you are not really saying anything about the oom behavior. With
this implementation the kernel will try to reclaim the memory and even
trigger the memcg oom killer if the request size is <= 8 pages. Is this
a desirable behavior?
-- 
Michal Hocko
SUSE Labs




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux