Messages in this thread |  | | Date | Wed, 4 Dec 2013 21:50:26 -0500 | From | Tejun Heo <> | Subject | Re: [patch 7/8] mm, memcg: allow processes handling oom notifications to access reserves |
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Hello,
On Wed, Dec 04, 2013 at 05:49:04PM -0800, David Rientjes wrote: > That's not what this series is addressing, though, and in fact it's quite > the opposite. It acknowledges that userspace oom handlers need to > allocate and that anything else would be too difficult to maintain > (thereby agreeing with the above), so we must set aside memory that they > are exclusively allowed to access. For the vast majority of users who > will not use userspace oom handlers, they can just use the default value > of memory.oom_reserve_in_bytes == 0 and they incur absolutely no side- > effects as a result of this series.
Umm.. without delving into details, aren't you basically creating a memory cgroup inside a memory cgroup? Doesn't sound like a particularly well thought-out plan to me.
> For those who do use userspace oom handlers, like Google, this allows us > to set aside memory to allow the userspace oom handlers to kill a process, > dump the heap, send a signal, drop caches, etc. when waking up.
Seems kinda obvious. Put it in a separate cgroup? You're basically saying it doesn't want to be under the same memory limit as the processes that it's looking over. That's like the definition of being in a different cgroup.
Thanks.
-- tejun
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