On Mon, Nov 09, 2015 at 03:08:32PM +0100, Michal Hocko wrote: ... > > Therefore this patch switches to the white list policy. Now kmalloc > > users have to explicitly opt in by passing __GFP_ACCOUNT flag. > > > > Currently, the list of accounted objects is quite limited and only > > includes those allocations that (1) are known to be easily triggered > > from userspace and (2) can fail gracefully (for the full list see patch > > no. 5) and it still misses many object types. However, accounting only > > those objects should be a satisfactory approximation of the behavior we > > used to have for most sane workloads. > > I am _all_ for this semantic I am just not sure what to do with the > legacy kmem controller. Can we change its semantic? If we cannot do that I think we can. If somebody reports a "bug" caused by this change, i.e. basically notices that something that used to be accounted is not any longer, it will be trivial to fix by adding __GFP_ACCOUNT where appropriate. If it is not, e.g. if accounting of objects of a particular type leads to intense false-sharing, we would end up disabling accounting for it anyway. > we would have to distinguish legacy and unified hierarchies during > runtime and add the flag automagically for the first one (that would > however require to keep __GFP_NOACCOUNT as well) which is all as clear > as mud. But maybe the workloads which are using kmem legacy API can cope > with that. > > Anyway if we go this way then I think the kmem accounting would be safe > to be enabled by default with the cgroup2. > > > Thanks, > > > > Vladimir Davydov (5): > > Revert "kernfs: do not account ino_ida allocations to memcg" > > Revert "gfp: add __GFP_NOACCOUNT" > > The patch ordering would break the bisectability. I would simply squash How's that? AFAICS the kernel should compile after any first N=1..5 patches of the series applied. > both places into the patch which replaces the flag. > IMO it is more readable the way it is, but I don't insist. Thanks, Vladimir > > memcg: only account kmem allocations marked as __GFP_ACCOUNT > > vmalloc: allow to account vmalloc to memcg > > Account certain kmem allocations to memcg -- 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>