On 08/15/2012 10:01 PM, Ying Han wrote: > On Wed, Aug 15, 2012 at 5:39 AM, Michal Hocko <mhocko@xxxxxxx> wrote: >> On Wed 15-08-12 13:33:55, Glauber Costa wrote: >> [...] >>>> This can >>>> be quite confusing. I am still not sure whether we should mix the two >>>> things together. If somebody wants to limit the kernel memory he has to >>>> touch the other limit anyway. Do you have a strong reason to mix the >>>> user and kernel counters? >>> >>> This is funny, because the first opposition I found to this work was >>> "Why would anyone want to limit it separately?" =p >>> >>> It seems that a quite common use case is to have a container with a >>> unified view of "memory" that it can use the way he likes, be it with >>> kernel memory, or user memory. I believe those people would be happy to >>> just silently account kernel memory to user memory, or at the most have >>> a switch to enable it. >>> >>> What gets clear from this back and forth, is that there are people >>> interested in both use cases. >> >> I am still not 100% sure myself. It is just clear that the reclaim would >> need some work in order to do accounting like this. >> >>>> My impression was that kernel allocation should simply fail while user >>>> allocations might reclaim as well. Why should we reclaim just because of >>>> the kernel allocation (which is unreclaimable from hard limit reclaim >>>> point of view)? >>> >>> That is not what the kernel does, in general. We assume that if he wants >>> that memory and we can serve it, we should. Also, not all kernel memory >>> is unreclaimable. We can shrink the slabs, for instance. Ying Han >>> claims she has patches for that already... >> >> Are those patches somewhere around? > > Yes, I am working on it to post it sometime *this week*. My last > rebase is based on v3.3 and now I am trying to get it rebased to > github-memcg. The patch itself has a functional dependency on kernel > slab accounting, and I am trying to get that rebased on Glauber's tree > but has some difficulty now. What I am planning to do is post the RFC > w/ only complied version by far. That would be great, so we can start looking at its design, at least. > The patch handles dentry cache shrinker only at this moment. That is > what we discussed last time as well, where dentry contributes most of > the reclaimable objects. (it pins inode, so we leave inode behind) > This will mark the inodes as reclaimable, but will leave them in memory. If we are assuming memory pressure, it would be good to shrink them too. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>